�Test 3 – Semiconductor

1. The name of pure semiconductor material that has an equal number of electrons and holesA. n-typeB. pure typeC. intrinsicD. p-typeANSWER: C

2. Elements that has four valence electrons are classified asA. conductorB. insulatorC. elemental semiconductorD. compound semiconductorANSWER: C

3. An example of an elemental semiconductor.A. Germanium (Ge)B. Gallium Arsenide (GaAs)C. Gallium Phosphide (GaP)D. Aluminum Arsenide (AlAs)ANSWER A

4. Which of the following is an example of a compound semiconductor?A. Gallium Arsenide (GaAs)B. Gallium Phosphide (GaP)C. Aluminum Arsenide (AlAs)D. All of the aboveANSWER: D

5. Germanium has an atomic number of 32 and an atomic weight of approximately 72 amu. How many electrons, protons and neutrons are there?A. 32, 32, 40B. 32, 32, 104C. 40, 32, 32D. 40, 32, 104ANSWER: A

6. The chemical bond that is present in a crystal lattice of silicon atoms.A. covalent bondB. electrovalent bondC. ionic bondD. metallic bondANSWER: A

7. The atomic weight of a silicon atom is approximately 28 amu. How many electrons, protons and neutrons does the atom consist?A. 14, 42, 14B. 14, 14, 42C. 42, 14, 14D. 14, 14, 14ANSWER: D8. What is the total charge at the nucleus of silicon atom?A. -12e CB. 12e CC. -14e CD. 14e CANSWER: D

9. In materials, what do you call the area that separates the valence band and the conduction band?A. energy gapB. forbidden bandC. insulation bandD. A and B are correctANSWER: B

10. At absolute zero temperature, semiconductor acts asA. an insulatorB. a conductorC. a semi-insulatorD. usualANSWER: A

11. The electron flow in a semiconductor material isA. opposite in direction of hole flowB. the same direction with hole flowC. the drift currentD. known as the conventional currentANSWER: A

12. Typical range of the resistivity of a semiconductorA. 10-15 – 10-18 Ω-cmB. 10-5 – 10-8 Ω-cmC. 10 – 104 Ω-cmD. 108 – 1015 Ω-cmANSWER: C

13. Chemical bond that is significant in metalsA. ionic bondingB. electrovalent bondingC. covalent bondingD. metallic bondingANSWER: D

14. A semiconductor that is free from impuritiesA. intrinsic semiconductorB. extrinsic semiconductorC. compensated semiconductorD. elemental semiconductorANSWER: A

15. The process of adding impurities in a semiconductor material.A. growingB. diffusionC. dopingD. depletingANSWER: C

16. Impurities with five valence electrons.A. acceptorB. donorC. trivalentD. pentavalentANSWER: D

17. Example of acceptor impurities.A. pentavalent impuritiesB. trivalent impurities

C. tetravalent impuritiesD. hexavalent impuritiesANSWER: B

18. If the substance used in doping has less than four valence electrons, it is known asA. acceptorB. donorC. trivalentD. pentavalentANSWER: A

19. Commonly used as donor impurities.A. Antimony (Sb)B. Arsenic (As)C. Phosphorus (P)D. all of the aboveANSWER: D

20. Example of trivalent impurities.A. Boron (B)B. Gallium (Ga)C. Indium (In)D. all of the aboveANSWER: D

21. Donor-doped semiconductor becomes aA. N-type semiconductorB. good conductorC. p-n semiconductorD. P-type semiconductorANSWER: A

22. What do you call a semiconductor that is doped with both donor and acceptor impurities?A. double doped semiconductorB. compensated semiconductorC. compound semiconductorD. diffused semiconductorANSWER: B23. The resistance of a semiconductor is known asA. bulk resistanceB. intrinsic resistanceC. extrinsic resistanceD. dynamic resistanceANSWER: A

24. The most extensively used semiconductor.A. siliconB. germaniumC. gallium phosphideD. gallium arsenideANSWER: A

25. Semiconductor whose electron and hole concentrations are equal.A. extrinsic semiconductorB. intrinsic semiconductorC. compensated semiconductorD. doped semiconductorANSWER: B

26. Silicon is widely used over germanium due to its several advantages, what do you think is its most significant advantage?A. abundantB. cheapC. temperature stableD. low leakage currentANSWER: D

27. Current flow in a semiconductor that is due to the applied electric field.A. diffusion currentB. conventional currentC. drift velocityD. drift currentANSWER: D

28. The movement of charge carriers in a semiconductor even without the application of electric potential.A. diffusion currentB. conventional currentC. drift currentD. saturation currentANSWER: A

29. Typically, how much energy is required for a valence electron to move to the conduction band for a doped semiconductor?A. 0 eVB. 0.05 eVC. 1.0 eVD. 5.0 eVANSWER: B

30. Conduction of electrons in a doped semiconductor happens atA. conduction bandB. forbidden bandC. valence bandD. nuclei bandANSWER: A

31. Theoretically, where does the conduction of holes occur in a doped semiconductor?A. conduction bandB. forbidden bandC. valence bandD. empty bandANSWER: C

32. In energy band diagram of a doped semiconductor, the donor levelA. is near the valence bandB. is near the conduction bandC. is exactly in between the valence and conduction bandD. depends on the amount of dopingANSWER: B

33. The acceptor level in a doped semiconductorA. is near the valence band levelB. is near the conduction levelC. is exactly in between the conduction and valence bandD. will depend on the concentration of dopingANSWER: A

34. In a semiconductor material, what will happen to the number of free electrons when the temperature rises?A. increasesB. decreases exponentiallyC. decreasesD. remains the sameANSWER: A

35. The electrical resistance of a semiconductor material will ________ as the temperature increases.A. increaseB. increase exponentiallyC. decreaseD. not changeANSWER: C

36. The potential required to removed a valence electronA. valence potentialB. threshold potentialC. critical potentialD. ionization potentialANSWER: D

37. Among the given elements, which is considered as nonmetal?A. silicon (Si)B. germanium (Ge)C. tin (Sn)D. lead (Pb)ANSWER: A

38. A semiconductor that is classified as a metalloid or semimetalA. silicon (Si)B. germanium (Ge)C. tin (Sn)D. carbon (C)ANSWER: B

39. Semiconductor that is very rare, it only occurs in minute quantities in many metal sulfidesA. silicon (Si)B. germanium (Ge)C. tin (Sn)D. lead (Pb)ANSWER: B

40. Compound semiconductors are also known asA. compensated semiconductorsB. amorphous semiconductorsC. organic semiconductorsD. inner-mettalic semiconductorsANSWER: D

41. What semiconductor that is mostly used in devices requiring the emission or absorption of lights?A. amorphous semiconductorB. organic semiconductorC. compound semiconductorD. elemental semiconductorANSWER: C

42. For high-speed integrated circuit, which semiconductor material given below is best to be used?A. siliconB. germaniumC. carbonD. gallium arsenideANSWER: D

43. How much impurity concentration is needed for a sample of silicon to change its electrical property from a poor conductor to a good conductor?A. one part per hundredB. one part per thousandC. one part per millionD. one part per billionANSWER: C

44. The restriction of certain discrete energy levels in a semiconductor material can be predicted generally by using what model?A. Bohr modelB. string modelC. wave modelD. particle modelANSWER: A

45. Is defined as the energy acquired by an electron moving through a potential of one volt.A. electron Joules (eJ)B. electron-potentialC. oxidation potentialD. electron Volt (eV)ANSWER: D

46. At room temperature, in a perfect silicon crystal, the equilibrium concentration of thermally generated electrons in the conduction band is aboutA. 1.5 x 105 per cubic cm.B. 1.5 x 1010 per cubic cm.C. 1.5 x 1015 per cubic cm.D. 1.5 x 1020 per cubic cm.ANSWER: B

47. What is the basis in operation of semiconductor photoconductors?A. EHP generationB. EHP degenerationC. EHP optical degenerationD. EHP optical generationANSWER: D

48. The semiconductor that is used in xerographyA. selenium (Se)B. gallium phosphide (GaP)C. cadmium compoundD. organic semiconductorANSWER: A

49. A silicon material has an intrinsic concentration ni=1010 per cubic centimeter at room temperature. If it is doped with 1015 antimony atoms per cubic centimeter, what is now the approximate electron concentration at the conduction band?A. 105 electronsB. 1010 electrons

C. 1015 electronsD. 1020 electronsANSWER: C

50. When an electron at the conduction band falls back to the valence band it will recombine with the hole. This is known asA. regenerationB. reunionC. combinationD. recombinationANSWER: D

51. Which semiconductor is mostly used to detect near infrared?A. siliconB. germaniumC. carbonD. silicon carbideANSWER: D

52. What semiconductor that is good for high-temperature applications?A. indium antimonide (InSb)B. gallium anitmonide(GaSb)C. silicon carbide (SiC)D. diamond (C)ANSWER: A

53. Among the given semiconductors below, which has the highest mobility?A. siliconB. germaniumC. gallium arsenideD. indium antimonideANSWER: D

54. A semiconducting glass is known asA. isomorphous semiconductorB. amorphous semiconductorC. organic semiconductorD. compound semiconductorANSWER: B

55. For an electroluminescent of green and red lights, which semiconductor is best?A. silicon carbideB. gallium arsenideC. indium antimonideD. gallium phosphideANSWER: D56. Typical range of power dissipation for a semiconductor to be considered as “low power” or “small signal”A. less than 1 wattB. 5 < P < 10 wattsC. 10 < P < 20 wattsD. 20 watts aboveANSWER: A

57. In the design of high power semiconductor devices, it involves what factors?A. making the size of the semiconductor biggerB. packing the device into a bigger caseC. excellent contact between the semiconductor and the caseD. all of the above

ANSWER: D

58. How to have a better high-frequency response in designing semiconductor devices?A. make the chip as small as possibleB. the leads should be made shorter and smallerC. smaller packagingD. all of the aboveANSWER: D

59. Before an electron can participate in the conduction of electricity, it must leave from the valence band and transfer to the conduction band. Transferring to the conduction band involves energy acquisition by an electron from external sources and this energy must be greater than the energy gap of the material. Which semiconductor material has the highest energy gap?A. Zinc Sulfide (ZnS)B. silicon (Si)C. germanium (Ge)D. Indium Antimonide (InSb)ANSWER: A

60. Which of the following semiconductors has the smallest energy gap?A. ZnSB. SiC. GeD. InSbANSWER: D

61. The ease with which a charge carrier (electron or hole) moves in a semiconductor material is known as mobility. It is also defined as the average drift velocity of electrons and holes per unit electrostatic field. Which of the semiconductor materials has the highest value of electron-mobility?A. InSbB. GeC. SiD. AlPANSWER: A

62. In semiconductor materials, electrons have a higher value of mobility than holes, but which semiconductor material has the slowest electron-mobility?A. InSbB. GaPC. GaAsD. AlPANSWER: D

63. Solar cell is a semiconductor electric-junction device, which absorbs the radiant energy of sunlight and converts it directly and efficiently into electrical energy. This device, uses what type of semiconductor materials?A. single-crystal siliconB. amorphous or polycrystalline siliconC. GaAs, CdS, CdTe, CuSD. all of the aboveANSWER: D

64. What is formed when n-type and p-type semiconductors are brought together?A. pn junctionB. semiconductor junctionC. energy band gapD. semiconductor diode

ANSWER: A

65. PN junction acts as a one way valve for electrons because _________.A. the circuit in which the diode is used, only attempts to pump electrons in one diodeB. electrons tend to follow the direction of the holeC. there is a little mechanical switch inside a diodeD. when electrons are pump from P to N, free electrons and holes are force apart leaving no way for electrons to cross the junctionANSWER: D

66. The device that is formed when an n-type and p-type semiconductors are brought togetherA. pn junctionB. semiconductor junctionC. depletion regionD. junction diodeANSWER: D

67. An external voltage applied to a junction reduces its barrier and aid current to flow through the junctionA. reverse biasB. external biasC. junction biasD. forward biasANSWER: D

68. A device containing an anode and a cathode or a pn junction of a semiconductor as the principal elements and provides unidirectional conduction.A. diodeB. diacC. triodeD. triacANSWER: A

69. Unidirectional conduction in two-electrodes in any device other than a diode, such that rectification between the grid and cathode of a triode, or asymmetrical conduction between the collector and base of a transistor is calledA. rectificationB. diode actionC. clippingD. clampingANSWER: B

70. The p-type material in a semiconductor junction diode is technically termed asA. positive terminalB. negative terminalC. cathodeD. anodeANSWER: D

71. Cathode in a semiconductor junction diode is referred to theA. positive terminalB. junctionC. p-type terminalD. n-type terminalANSWER: D

72. The area in the semiconductor diode where there are no charge carriers

A. depletion layerB. depletion regionC. depletion modeD. depletion areaANSWER: B

73. Depletion region is an area in a semiconductor device where there are no charge carriers exist. This will be always near the junction of n-type and p-type materials. What causes this junction to be depleted by charge carriers?A. Due to the recombination of holes and electrons at the junctionB. Due to the cancellation of positively charge protons and negatively charge electronsC. Due to the annihilation of charge carriersD. Due to the combination of positively charge holes and negatively charge electronsANSWER: D

74. A junction diode is said to be forward-biased ifA. Anode is supplied more positive than the cathode.B. Anode is supplied more negative than the cathode.C. A voltage greater than threshold is applied, with cathode less positive than anode.D. A voltage greater than threshold is applied, with cathode less negative than anode.ANSWER: C

75. What do you call the very small amount of current that will flow in the diode when it is reverse biased?A. saturation currentB. reverse saturation currentC. cut-off currentD. holding currentANSWER: B

76. When the diode is supplied with forward direction potentials but with a magnitude less than the threshold voltage of the diode, still it will not “turn-on” and will only allow a very small amount of current to pass. This very small current is knownA. as leakage currentB. as forward saturation currentC. as holding currentD. as cut-off currentANSWER: D

77. The minimum voltage required before a diode can totally conduct in a forward direction.A. triggering voltageB. breakdown voltageC. saturation voltageD. threshold voltageANSWER: D

78. What will happen to the threshold voltage of the diode when it operates at higher temperatures.A. increasesB. increases exponentiallyC. decreasesD. decreases exponentiallyANSWER: C

79. The forward current in a conducting diode will ______________ as the operating temperature increases.A. not be affectedB. decreaseC. decrease exponentiallyD. increaseANSWER: D

80. As the operating temperature of a reverse-biased diode is increased, its leakage or reverse saturation current willA. IncreaseB. increase exponentiallyC. decreaseD. decrease exponentiallyANSWER: B

81. The small value of direct current that flows when a semiconductor device has reverse biasA. surge currentB. bias currentC. reverse currentD. current limitANSWER: C

82. Normally, diodes will not conduct when reverse-biased, but if the reverse voltage is increased further, a point will be reached where the diode gives up and allowing the current to surge. This voltage is one of the limiting parameter of diodes and is known asA. breakdown voltage (VBR)B. peak inverse voltage (PIV)C. peak reverse voltage (PRV)D. all are correctANSWER: D

83. For a silicon diode, calculate the current at room temperature if the forward voltage VF = 0.3 V and the reverse saturation current IS = 100 nA.A. 32.8 μAB. 10.8 μAC. 32.8 mAD. 10.8 mAANSWER: A

84. The breakdown voltage of a junction diode will ___________A. Increase as operating temperature rises.B. Increase exponentially as operating temperature rises.C. Decrease as operating temperature rises.D. Not change as operating temperature rises.ANSWER: C85. Calculate the new threshold voltage of a germanium diode when it operates at 100 0C.A. 0.113 VB. 0.188 VC. 0.215 VD. 0.513 VANSWER: A

86. A silicon diode has a reverse saturation current of 50 nA at room temperature. If the operating temperature is raised by 50°C, what is now the reverse saturation current?A. 105.56 nA

B. 287.73 nAC. 827.89 nAD. 1.66 μAANSWER: D

87. In every increase of 10°C in the operating temperature of a diode will cause its reverse saturation current toA. decreaseB. doubleC. tripleD. quadrupleANSWER: B

88. What do you call the resistance of the diode when operating at a steady state voltage?A. dc resistanceB. dynamic resistanceC. ac resistanceD. average resistanceANSWER: A

89. The resistance of the diode that is significant when operating with a small ac signalA. dc resistanceB. static resistanceC. dynamic resistanceD. average resistanceANSWER: C

90. When a diode is used in large ac voltages, the resistance that is to be considered isA. dc resistanceB. static resistanceC. dynamic resistanceD. average resistanceANSWER: D

91. At forward bias condition, what will happen to the diode resistance when the applied voltage is increased?A. will also increaseB. will increase exponentiallyC. will decreaseD. will not changeANSWER: C

92. The primary use of Zener diode in electronic circuits.A. resistance regulatorB. rectifierC. voltage regulatorD. current regulatorANSWER: C

93. What phenomenon in electronics does an avalanche breakdown primarily dependent?A. DopingB. RecombinationC. IonizationD. CollisionANSWER: C

94. When a diode is reverse biased the depletion region widens, since it is in between positively charge holes and negatively charge electrons, it will have an effect of a capacitor, this capacitance is called what?A. diffusion capacitanceB. storage capacitanceC. stray capacitanceD. transition capacitanceANSWER: D

95. In a semiconductor diode, the total capacitance, that is the capacitance between terminals and electrodes, and the internal voltage variable capacitance of the junction is calledA. diffusion capacitanceB. transition capacitanceC. depletion-region capacitanceD. diode capacitanceANSWER: D

96. What capacitance is significant when the diode is forward biased?A. diffusion capacitance or storage capacitanceB. transition capacitanceC. depletion-region capacitanceD. stray capacitanceANSWER: A

97. A diode that is especially designed to operate as a voltage-variable capacitor. It utilizes the junction capacitance of a semiconductor diode.A. varactorB. varicapC. varistorD. A and B are correctANSWER: D

98. The capacitance of a varactor will _______ when the forward bias voltage is increased.A. increaseB. decreaseC. exponentially decreaseD. not changeANSWER: A

99. The time taken by the diode to operate in the reverse condition from forward conductionA. reverse recovery timeB. forward recovery timeC. reverse holding timeD. reverse time constantANSWER: A

100. In operating a diode at high-speed switching circuits, one of the most important parameters to be considered isA. ac resistanceB. diode capacitanceC. noise figureD. reverse recovery time (trr)ANSWER: D

101. The time required for forward voltage or current to reach a specified value after switching the diode from its reverse-to-forward-biased state.A. reverse recovery time

B. forward recovery time (tfr)C. saturation timeD. conduction timeANSWER: B

102. The maximum power the diode can handle.A. maximum derating powerB. maximum consumption powerC. breakdown powerD. maximum dissipation powerANSWER: D

103. What is the most important specification for semiconductor diode?A. Forward resistanceB. Reverse resistanceC. Peak inverse voltageD. Current capacityANSWER: D

104. What will happen to the power handling capability of the diode if it is to be operated at a higher temperature?A. decreasesB. increasesC. increases exponentiallyD. will not be affectedANSWER: A

105. Diode parameter that will inform the user as to what factor does the power handling capability of the diode is reduced as the operating temperature is increased.A. power derating factorB. power dissipating factorC. power reduction constantD. all of the aboveANSWER: A

106. A certain diode has a maximum power dissipation of 500 mW at room temperature and a linear power derating factor of 5.0 mW/°C. How much power the diode can handle if operated at 50°C.A. 625 mWB. 505 mWC. 495 mWD. 375 mWANSWER: D

107. A semiconductor device especially fabricated to utilize the avalanche or zener breakdown region. This is normally operated in the reverse-region and its application is mostly for voltage reference or regulation.A. varactor diodeB. zener diodeC. shockley diodeD. Schottky barrier diodeANSWER: B

108. Refers to a special type of diode which is capable of both amplification and oscillation.A. Junction diodeB. Tunnel diodeC. Point contact diodeD. Zener diode

ANSWER: B

109. The effect obtain when the electric field across a semiconductor is strong enough which causes the free electrons to collide with valence electrons, thereby releasing more electrons and a cumulative multiplication of charge carriers occur.A. GunnB. avalancheC. tunnelingD. diffusionANSWER: B110. A negative resistance diode commonly used in microwave oscillators and detectors, it is sometimes used as amplifiers. This device is also known as Esaki diode.A. varactor diodeB. Schottky diodeC. IMPATT diodeD. tunnel diodeANSWER: D

111. A rectifying metal-semiconductor junctionA. Schottky barrier diodeB. surface barrier diodeC. hot-carrier or hot-electron diodeD. all of the above are correctANSWER: D

112. Diode whose negative resistance depends on a specific form of quantum-mechanical bond structure of the materialA. Gunn diodeB. tunnel diodeC. TRAPATT diodeD. backward diodeANSWER: A

113. One of the electronic semiconductor devices known as diac, function asA. Four terminal multi-directional switchB. Two terminal bi-directional switchC. Two terminal unidirectional switchD. Three terminal bi-directional switchANSWER: C

114. Another name of a three-layer diode. This is also considered as an ac diode.A. Shockley diodeB. thyrectorC. thyristorD. diacANSWER: D

115. A diode whose negative resistance is dependent on the classical effects of phase shift introduced by the time lag between maximum field and maximum avalanche current, and by the transit time through the device.A. Read diodeB. IMPATT diodeC. TRAPATT diodeD. all of the aboveANSWER: D

116. What semiconductor diode that have a fine wire (called a cat-whisker) whose

point is in permanent contact with the surface of a wafer of semiconductor material such as silicon, germanium or gallium arsenide?A. point-contact diodeB. diacC. PiN diodeD. thyrectorANSWER: A

117. When the p-n junction of a semiconductor diode is inserted with an intrinsic material, the diode becomes aA. backward diodeB. Read diodeC. Schokley diodeD. PiN diodeANSWER: D

118. A four layer semiconductor diode whose characteristic at the first quadrant is similar to that of a silicon-controlled rectifier (SCR).A. Shockley diodeB. thyrectorC. Schottky diodeD. diacANSWER: A

119. A diode that is especially processed so that its high-current flow takes place when the junction is reverse-biased. It is a variation of a tunnel diode.A. Esaki diodeB. Read diodeC. zener diodeD. backward diodeANSWER: D

120. A silicon diode that exhibits a very high resistance in both directions up to certain voltage, beyond which the unit switches to a low-resistance conducting state. It can be viewed as two zener diodes connected back-to-back in series.A. bizener diodeB. diacC. thyristorD. thyrectorANSWER: D

121. A type of Read diode that uses a heavily doped n-type material as its drift regionA. IMPATT diodeB. TRAPATT diodeC. TUNNETT diodeD. MITATTANSWER: A122. A device containing more than one diode. An example is the full-wave bridge-rectifier integrated circuit.A. diode arrayB. diode ICC. diode packD. combined diodeANSWER: C

123. Is the combination of the inductance of the leads and electrodes, capacitance of the junction, and the resistance of the junction of a semiconductor diode.A. diode impedanceB. diode ac resistance

C. diode reactanceD. diode ac parameterANSWER: A

124. In a reverse-biased pn junction, the sudden large increase in current that occurs when a particular value of reversed voltage is reached, and which is due to ionization by the high intensity electric field in the depletion region.A. Zener effectB. Hall effectC. breakdown voltageD. ionizationANSWER: A

125. The appearance of RF current oscillations in a dc-biased slab of n-type gallium arsenide in a 3.3 kV electric fieldA. Gunn effectB. Hall effectC. Zener effectD. avalancheANSWER: A

126. The impedance presented by a junction operating in its zener breakdown region.A. diode impedanceB. zener impedanceC. breakdown impedanceD. critical impedanceANSWER: B

127. A curve showing the relationship between the voltage and the current of the diode at any given temperatureA. characteristic curveB. transfer curveC. transfer characteristic curveD. all are correctANSWER: A128. The line that is plotted in the diode characteristic curve which represents the loadA. linear lineB. operating lineC. load lineD. transfer load lineANSWER: C

129. Diode is said to be operating at a point where the characteristic curve and the load line intersect. This point is technically termed asA. Q-pointB. operating pointC. quiescent pointD. all are correctANSWER: D

130. What will happen to the magnitude of the load-line slope when the load resistance is decreased?A. it will also decreaseB. it will increaseC. it will increase exponentiallyD. is not affected by the loadANSWER: B

131. Q-point position is dependent onA. the supply voltageB. the load resistanceC. the type of diodeD. all of the aboveANSWER: D

132. A germanium diode is connected to a load resistance of 1.5 kΩ and is supplied with 12-V such that the diode will be forward biased. What is the voltage across the diode?A. approximately 12 VB. approximately 0.7 VC. approximately 0.3 VD. lack of data and can’t be solvedANSWER: C

133. What is the drop across the diode when it is connected in series to a resistor of 1.8 kΩ and a supply voltage of 50 V. The supply voltage causes the diode to be reverse-biased.A. 50 VB. 0.7 VC. 0.3 VD. can not be solve, lack of dataANSWER: A

134. Two germanium diodes are connected in series and have a load resistance of 10 kΩ and a forward supply voltage of 5 V. Calculate the voltage across the load resistor.A. 4.7 VB. 4.4 VC. 0.6 VD. 0.3 VANSWER: B

135. A silicon diode is in parallel with a germanium diode and is connected to a load resistor having a value of 20 kΩ and a forward supply voltage of 10 V. What is the approximate voltage across the silicon diode?A. 10 VB. 1.0 VC. 0.7 VD. 0.3 VANSWER: D

136. What is the output voltage across a load resistor if it is paralleled with a forward biased silicon diode? The resistor network is supplied with 10 V.A. 0.7 VB. 9.3 VC. 10 VD. Can’t be solve, lack of data.ANSWER: A

137. Diode circuit that is used to cut a portion of the input signalA. clipperB. clamperC. peak detectorD. level shifterANSWER: A

138. A clipper circuit wherein the diode is connected in series with the loadA. series clipper

B. parallel clipperC. shunt clipperD. series feed clipperANSWER: A

139. What do you call a clipper circuit wherein the diode is shunted with the load?A. series clipperB. parallel clipperC. cascade clipperD. cascade clipperANSWER: B

140. A network with a diode and a capacitor that is used to shift the dc-level of the input signalA. clipperB. clamperC. shifterD. level inverterANSWER: B

141. Half-wave rectifier is a good example ofA. a series clamperB. a parallel clamperC. a parallel clipperD. a series clipperANSWER: D

142. Which of the given circuit below must have a capacitor?A. rectifierB. clipperC. clamperD. all of the aboveANSWER: C

143. How many capacitors are used in a diode-capacitor half- wave voltage doubler?A. 1B. 2C. 3D. 4ANSWER: B

144. An improvement of a diode-capacitor half-wave voltage doubler is the full-wave doubler, this circuit uses how many capacitors?A. 1B. 2C. 3D. 4ANSWER: B

145. In a diode-capacitor voltage quadrupler, what is the voltage across the third stage capacitor?A. VmaxB. 2 VmaxC. 3 VmaxD. 4 VmaxANSWER: B

146. A combination of several diodes in a single housing

A. diode arrayB. diode networkC. diode ICD. diode matrixANSWER: A

147. A chopper, employing an alternately biased diodes as the switching element.A. diode chopperB. active chopperC. junction chopperD. all are correctANSWER: A

148. A light emitting diode (LED) is to be used in a circuit with a supply voltage of 5 V. What should be the value of the resistor needed by the LED to operate normally?A. 25 ΩB. 250 ΩC. 25 kΩD. 250 kΩANSWER: B

149. A simple voltage-regulator whose output is the constant voltage drop developed across a zener diode conducting in the reverse breakdown region. The regulator circuit consists of a zener diode in parallel with the load and an appropriate limiting resistor.A. ordinary voltage regulatorB. zener voltage regulatorC. series voltage regulatorD. switching voltage regulatorANSWER: B

150. Logic circuitry in which a diode is the logic element and a transistor acts as an inverting amplifier.A. RTLB. DTLC. HDTLD. ECLANSWER: B

151. What is a bridge rectifier having diodes in two arms and resistors in the other two?A. full-wave bridgeB. half-wave bridgeC. half-bridgeD. full bridgeANSWER: C

152. An over-voltage protection circuit employing a zener diode and an SCR whose function is to produce high overload by-pass current on a circuit.A. regulatorB. current enhancerC. crowbarD. shunted zenerANSWER: C

153. The flow of electron in a NPN transistor when used in electronic circuit is from _______.A. collector to baseB. collector to base

C. emitter to collectorD. base to emitterANSWER: C

154. A three terminal, three layer semiconductor device that has the ability to multiply charge carriers. This device was first introduced at Bell Laboratories, by Brattain and Bardeen in 1947 and which opens a completely new direction of interest and development in the field of electronics.A. triodeB. triacC. SCRD. transistorANSWER: D

155. An active semiconductor device, capable of amplification, oscillation, and switching action. It is an acronym for transfer resistor and had replaced the tube in most applications.A. thyristorB. thyrectorC. SBSD. transistorANSWER: D

156. Transistor replaces the old vacuum tubes because it has several obvious advantages, what are they?A. smaller, lightweight and rugged constructionB. no heater loss, low operating voltage and therefore efficientC. low power consumption and low power dissipationD. all of the aboveANSWER: D

157. Which of the three regions/areas in a transistor that is the smallest in construction?A. emitterB. collectorC. baseD. all are equalANSWER: C

158. The region or area in a transistor that is heavily dopedA. at the junctionB. emitterC. collectorD. baseANSWER: B

159. A transistor in which the base is diffused and the emitter is alloyed. The collector is provided by the semiconductor substrate into which alloying and diffusion are affected.A. alloy-transistorB. alloy-diffused transistorC. alloy junction transistorD. diffused junction transistorANSWER: B

160. A transistor whose junctions are created by alloyingA. alloy transistorB. alloy-diffused transistorC. diffused transistorD. alloy junction

ANSWER: A

161. In a semiconductor device, a p-n junction formed by alloying a suitable material such as indium with the semiconductor.A. alloy junctionB. diffused junctionC. depletion junctionD. storage junctionANSWER: A

162. A transistor in which one or both electrodes are created by diffusionA. diffused transistorB. alloy transistorC. planar transistorD. mesa transistorANSWER: A

163. A two-junction transistor whose construction takes the form of a pnp or a npn. Such device uses both electron and hole conduction and is current-driven.A. bipolar transistorB. unipolar transistorC. bi-directional transistorD. double junction transistorANSWER: A

164. The predecessor of the junction transistor, and is characterized by a current amplification factor, alpha of greater than one.A. surface-charge transistorB. surface-barrier transistorC. schottky transistorD. point-contact transistorANSWER: D

165. For a transistor, the outer layers areA. lightly doped semiconductorsB. heavily doped semiconductorsC. no doping at allD. A and B aboveANSWER: B

166. The ratio of the total width of the outer layers to that of the center layerA. 100:1B. 150:5C. 150:1D. 1:150ANSWER: C

167. The ratio of the doping level of the outer layers to that of the sandwiched materialA. 10:3 or moreB. 10:2 or moreC. 10:3D. 10:1 or lessANSWER: D

168. Limiting the number of “free” carriers willA. increase the conductivity but decreases the resistanceB. decrease the conductivity but increases the resistanceC. increase the conductivity as well as resistivity

D. decrease the conductivity as well as resistivityANSWER: B

169. The term ________ reflects the fact that holes and electrons participate in the injection process into the oppositely polarized material.A. unipolarB. bipolarC. tetrodeD. pentodeANSWER: B

170. What device, that employs only electron or hole?A. unipolarB. bipolarC. tetrodeD. pentodeANSWER: A

171. At forward-biased junction of pnp transistor, majority carriers flow heavilyA. from p- to the n-type materialB. from n- to the p-type materialC. from p- to p-type materialD. A and B aboveANSWER: A

172. The minority-current component of a transistor is calledA. leakage currentB. emitter currentC. cut-off currentD. all of the aboveANSWER: A

173. For general-purpose transistors, IC is measured in ____, while ICO is measured in ____.A. micro and nanoamperesB. milliamperes and microamperesC. milliamperes and nanoamperesD. b and c aboveANSWER: D

174. Is temperature sensitive, and can severely affect the stability of the system, when not carefully examined during designA. ICB. ICOC. ISD. IEANSWER: B

175. For the transistor, the arrow in the graphic symbol defines the direction of _______ through the deviceA. leakage current flowB. emitter electron flowC. majority carrier flowD. emitter conventional current flowANSWER: D

176. In the dc mode, the levels of IC and IE due to the majority carriers are related by the quantityA. alpha (α)

B. bet� (β)

C. gamma (γ)D. A

�nd B

�bove

ANSWER: A

177. In the �c mode,

�lph

� α is form

�lly c

�lled

A. common-b�se, short-circuit,

�mplific

�tion f

�ctor

B. common-emitter, �mplific

�tion f

�ctor

C. common-collector, �mplific

�tion f

�ctor

D. �ll of the

�bove

�re correct

ANSWER: A

178. Phr�ses “not pointin

� in”

�nd “pointin

� in” simply me

�n

A. npn �nd pnp

B. pnp �nd npn

C. npn onlyD. pnp onlyANSWER: A

179. In the dc mode, the levels of IC �nd IB

�re rel

�ted by

� qu

�ntity c

�lled

A. αB. βC. γD. A

�nd B

�bove

ANSWER: B

180. For pr�ctic

�l tr

�nsistor devices, the level of β typically ranges

A. from a�out 25 to over 400

B. less than 1C. mostly in midrange of 50 to 400D. A or C a

�ove

ANSWER: C

181. The formal name of βacA. Common-collector reverse-current amplification factorB. Common-collector forward-current amplification factorC. Common-emitter forward-current amplification factorD. Common-emitter reverse-current amplification factorANSWER: C

182. It is a particularly important parameter that provides a direct link �etwee

n current levels of the input and output circuits for a common-emitter configuration.A. αB. βC. A and B a

�ove

D. none of the a�ove

ANSWER: B

183. The _______ id defined as that area �elow IC= ICEO.

A. active regionB. cutoff regionC. saturation regionD. none of the a

�ove

ANSWER: B

184. It is referred to as the communication link �etween the manufacturer and us

erA. specification sheetB. characteristic manual

C. characteristic curveD. all of the a

�ove

ANSWER: D

185. The information that can �e found in most specification sheets?

A. maximum ratingsB. thermal characteristicsC. electrical characteristicsD. all of the a

�ove

ANSWER: D

186. With an ohmmeter, a large or small resistance in either junction of an npn or pnp transistor indicatesA. faulty deviceB. well functioning deviceC. leaky deviceD. either A or CANSWER: A

187. At �ase-emitter junction, using an ohmmeter, if the positive (+) lead is co

nnected to the �ase and the negative (-) lead to the emitter, a low resistance r

eading would indicateA. npn transistorB. pnp transistorC. germanium transistorD. silicon transistorANSWER: A

188. At �ase-emitter junction, if the positive (+) lead is connected to the

�ase

and the negative (-) lead to the emitter, a high resistance reading would indicateA. npn transistorB. pnp transistorC. germanium transistorD. silicon transistorANSWER: B

189. Transistors of heavy duty constructionA. high-power devicesB. low-power devicesC. medium-power devicesD. all of the a

�ove

ANSWER: A

190. On a voltage-current condition curve, the point �elong to which a further i

ncrease in voltage produces no (or very little) further increase in current.A. saturation fluxB. saturation valueC. saturation pointD. all of the a

�ove

ANSWER: C

191. It is applied to any system where levels have reached their maximum valuesA. saturationB. activeC. cutoffD. quiescent pointANSWER: A

192. For an “on” transistor, the voltage VBE should �e in the neigh

�orhood of

A. 0.3 VB. 0.55 VC. 0.7 VD. 1.7 VANSWER: C

193. Among the three characteristics of a transistor amplifier, which region is normally employed for linear (undistorted) amplifiers?A. active regionB. cutoff regionC. saturation regionD. capital regionANSWER: A

194. In the active region, the collector-�ase junction is ________, while the

�a

se-emitter junction is ________.A. forward and forward-

�iased

B. forward and reverse-�iased

C. reverse and reverse �iased

D. reverse and forward-�iased

ANSWER: D

195. It is necessary, in order to esta�lish the proper region of operation for a

c amplification.A. ac

�iasing

B. dc �iasing

C. A and B a�ove

D. none of the a�ove

ANSWER: B

196. At cutoff region, the collector-�ase and

�ase-emitter junctions of a transi

stor areA.

�oth reverse-

�iased

B. forward and reverse-�iased

C. �oth forward-

�iased

D. reverse and forward-�iased

ANSWER: A

197. In saturation region, the collector-�ase and

�ase-emitter junctions of a tr

ansistor areA.

�oth reverse-

�iased

B. forward and reverse-�iased

C. �oth forward-

�iased

D. reverse and forward-�iased

ANSWER: C

198. If the �ase-emitter junction is reverse

�iased and the

�ase-collector junct

ion is forward �iased, the transistor will

�e at what region of operation?

A. active regionB. cut-off regionC. saturation regionD.

�reakdown region

ANSWER: B

199. Under what region does the transistor operate if �oth the

�ase-emitter and �

ase-collector junctions are reverse-�iased?

A. active regionB. cut-off regionC. saturation regionD.

�reakdown region

ANSWER: B

200. What region the transistor should �e operating to have minimum distortion a

t the output signal?A. active regionB. cut-off regionC. saturation regionD. none of the a

�ove

ANSWER: A

201. In dc �iasing, it means quiet, still, inactive

A. passiveB. quenchC. staticD. quiescentANSWER: D

202. The transistor terminal that handles most currentA.

�ase

B. collectorC. emitterD. collector and emitterANSWER: C

203. Which indicates the degree of change, in operating-point due to temperature variation in the dc

�iasing?

A. temperature coefficientB. factor of safetyC. merit factorD. sta

�ility factor

ANSWER: D

204. What �est descri

�es the transistor current that flows

�etween the collector

and emitter terminals when the �ase is open?

A. leakage currentB. cut-off currentC. reverse saturation currentD. all of the a

�ove

ANSWER: B

205. Solve for the �ase current if collector current is 600 mA and the current g

ain is 20.A. 30 mAB. 3 mAC. 12 mAD. 1.2 mAANSWER: A

206. When the transistor is saturated, VCE is approximatelyA. 0 VB. ½ VCCC. VCCD. infiniteANSWER: A

207. Collector-emitter resistance of ideal transistor at cut-offA. 0 ΩB. infiniteC. a function of the load resistanceD. a function of the collector current

ANSWER: B

208. The leakage current that flows at the collector-base junction when the emitter is openA. ICOB. ICBOC. ICEOD. ICBEANSWER: B

209. A transistor with β = 100 is connected as common �ase, was found to have a le

akagecurrent ICBO = 1μA. If the transistor is configured as common emitter, what is theapproximate value of its ICEO?A. 0.01 μAB. 1.0 μAC. 100 μAD. 10 mAANSWER: C

210. The most correct technical term of the reverse leakage current that flows between thecollector and base junctions when the emitter is open circuited.A. leakage currentB. saturation currentC. reverse saturation currentD. cut-off currentANSWER: C

211. How is the collector cut-off or reverse saturation current ICBO related to the emitter cutoffcurrent IEBO?A. ICBO � β IEBO pB. ICBO � IEBO/βC. ICBO � IEBO(1-α)D. ICBO � IEBOANSWER: D

212. ICBO of �n ide

�l tr

�nsistor

A. incre�ses

�s temper

�ture incre

�ses

B. incre�ses

�s temper

�ture decre

�ses

C. is not �ffected by

� temper

�ture ch

�n�e

D. is zero (0) mAANSWER: D

213. The m�ximum volt

��e th

�t c

�n be

�pplied

�cross the collector-emitter termin�

l for ��

iven tr�nsistor is specified

�s

A. VCEOB. VECOC. V(BR)BEOD. V(BR)CEOANSWER: D

214. If the current-��

in-b�ndwidth product of tr

�nsistor is 250 MHz

�nd is oper

�ted

�t 100

MHz, wh�t is the effective current

��in of the tr

�nsistor?

A. 2.5B. 25C. 250

D. 350ANSWER: A

215. The current ��

in of � tr

�nsistor decre

�ses

�s the oper

�tin

� frequency incre�

ses. As the oper�tin

� frequency is incre

�sed continuously,

� point occurs where

the current ��

in becomes unity. This point, is best described by wh�t tr

�nsisto

r p�r�meter?

A. unity ��

in frequencyB. 0 dB frequencyC. cut-off frequencyD. unity

��in b

�ndwidth product or unity current

��in b

�ndwidth product

ANSWER: D

216. When b�se is common to both the input

�nd output sides of the confi

�ur

�tion

�nd is usu

�lly the termin

�l closes to, or

�t �round potenti

�l, it is c

�lled wh

�t?A. common-emitter terminolo

�y

B. common-collector terminolo�y

C. common-b�se terminolo

�y

D. �ll of the these

ANSWER: C

217. Which tr�nsistor confi

�ur

�tion h

�s the hi

�hest input resist

�nce?

A. common b�se

B. common emitterC. common collectorD. common tr

�nsistor

ANSWER: C

218. One of the followin� �mplifier ch

�r�cteristic refers to th

�t of

� common-b

�se (C-B)

�s comp

�red to common-emitter (C-E)

�nd common-collector (C-C)

�mplifie

rs.A. H

�s l

�r�er current

��in

B. H�s lower input resist

�nce

C. H�s hi

�her input resist

�nce

D. H�s l

�r�er volt

��e ��

inANSWER: B

219. A tr�nsistor is s

�id to be confi

�ured

�s common emitter if the emitter term

in�l is

A. �rounded

B. connected to V+C. flo

�tin

�D. not used

�s

�n input nor output

ANSWER: D

220. Most frequently used tr�nsistor confi

�ur

�tion for pnp

�nd npn

A. common-b�se

B. common-collectorC. common-emitterD. A

�nd C

�bove

ANSWER: C

221. C�lcul

�te the common-emitter

�mplific

�tion f

�ctor β of a transistor with a co

mmon-�ase amplification factor α=0.99.

A. 10B. 50C. 100D. 200ANSWER: C

222. Which tr�nsistor confi

�ur

�tion hybrid p

�r�meters, th

�t is usu

�lly specified

by the m�nuf

�cturers?

A. for common-b�se

B. for common-collectorC. for common-emitterD.

� combin

�tion of the three confi

�ur

�tions

ANSWER: C

223. For � common-emitter tr

�nsistor confi

�ur

�tion, the hybrid p

�r�meter hfe st

�nds for forw

�rd tr

�nsfer current r

�tio. This p

�r�meter is

�pproxim

�tely equ

�l to

A. HFEB. βacC. βD. all of the a

�ove

ANSWER: D

224. Hy�rid parameter that is usually neglected in circuit analysis

A. hi and hoB. hr and hfC. hi and hfD. hr and hoANSWER: D

225. The input impedance of a common-�ase configuration is hi

�, and its magnitud

e is approximately equal toA. hie/hfeB. hie/(1+β)C. re for dynamic modelD. all of theseANSWER: D

226. In most transistor input equivalent circuit it comprises of a resistor and aA. voltage sourceB. stiff voltage sourceC. current sourceD. stiff current sourceANSWER: A

227. Which transistor configuration has the highest input resistance?A. common-

�ase

B. common-collectorC. common-emitterD. emitter followerANSWER: B

228. Common-�ase configuration has a high voltage gain and a current gain of

A. lowB. moderateC. highD. approximately equal to one (1)ANSWER: D

229. Common-collector has the lowest power gain and a voltage gain of approximately one. In contrast to this, what configuration has the highest power gain?A. common-

�ase

B. common-collectorC. common-emitterD. emitter follower

ANSWER: C230. Which of the following transistor characteristic curves that is most useful?A. input characteristic curveB. output characteristic curveC. transfer characteristic curveD. all of the a

�ove

ANSWER: B

231. The graph of the product of collector-emitter voltage VCE and collector current IC in the transistor output characteristic curve.A. maximum power curveB. minimum power curveC. saturation power curveD.

�reakdown curve

ANSWER: A

232. The �ase of a transistor serves a purpose to what element of the FET?

A. sourceB. groundC. su

�strate

D. gateANSWER: D

233. What is the primary difference �etween the BJT and the FET?

A. current-controlled device and voltage-controlled device, respectivelyB. voltage-controlled device and current-controlled device, respectivelyC. impedance transformed device and conductance transformed device, respectivelyD. A and C a

�ove are correct

ANSWER: A

234. Another difference �etween a BJT and a FET with regards to its normal

�iasi

ng.A. The input circuit is forward-

�iased for BJT while reverse for FET.

B. The input circuit is reverse-�iased for BJT while forward for FET.

C. The output circuit is forward-�iased for BJT while reverse for FET.

D. The output circuit is reverse-�iased for BJT while forward for FET.

ANSWER: A

235. Field-effect transistors (FETs) offer high input impedance than BJT. What makes FETs have high input impedance?A. The way FETs are constructed.B. Because of the materials used.C. Due to the level of dopingD. Due to the reverse-

�iased input circuit of FETs

ANSWER: D

236. The operation of BJT involves �oth the flow of electrons and holes and is t

herefore, considered as a �ipolar device. Unlike BJT, FET’s operation involves onl

y either electrons or holes and is considered as a _________ device.A. single polarB. unipolarC. unpolarD. polarizedANSWER: B

237. Considered as the �asic FET or the simplest form of FET

A. JFETB. MOS-FETC. IGFET

D. VMOS-FETANSWER: A

238. Junction field effect transistor or JFET has three terminals, which corresponds to the E-B-C of the BJT?A. D-S-GB. D-G-SC. S-G-DD. S-D-GANSWER: C

239. One o�vious advantage of a JFET over BJT is its

A. high voltage gainB. high current gainC. high input resistanceD. high output resistanceANSWER: C

240. A BJT is a current-controlled current-source device while JFET is a _________ device.A. current-controlled voltage-sourceB. voltage-controlled voltage-sourceC. voltage-controlled current-sourceD. voltage-controlled transconductance-sourceANSWER: C

241. What do you call the area in a JFET where current passes as it flows from source (S) to drain (D).A. channelB. su

�strate

C. depletionD. driftANSWER: A

242. What will happen to the channel of a JFET as current flows to it?A. widensB. narrowsC. skewsD. nothingANSWER: C

243. For a normal operation of an n-channel JFET, how do you �ias the gate-sourc

e junction?A. positive-negative respectivelyB. negative-positive respectivelyC. forward-

�iased

D. any of the a�ove

ANSWER: B

244. The voltage across the gate-source terminal of a FET that causes drain current ID equal to zero.A. saturation voltageB. threshold voltageC. cut-off voltageD. pinch-off voltageANSWER: D

245. The current that flows into the channel of a JFET when the gate-source voltage is zero.A. drain-source saturation current

B. drain-source cut-off currentC. drain-source leakage currentD. drain-source pinch-off currentANSWER: A

246. The graph of the drain current ID versus drain-source voltage VDS with VGS as the parameter.A. transfer characteristic curveB. output characteristic curveC. input characteristic curveD. current-voltage characteristic curveANSWER: D

247. In FET, the conduction path of the output is controlled �y the electric fie

ld as its name implies. How does an electric field in FET esta�lished?

A. By the charges present at the gate due to the reverse-�iased junction.

B. By the application of reverse-�iased

�etween the gate and drain.

C. By the charges produced due to the applied potential �etween drain and source

VDS.D. By the charges present at each terminal due to the applied potential.ANSWER: A

248. An early version of the field effect transistor in which limited control of current carriers near the surface of a semiconductor

�ar or film was o

�tained

�y an external electric field applied transversely.A. fieldistorB. JFETC. IGFETD. MOSFETANSWER: A

249. A FET in which the gate electrode consists of a pn junctionA. JFETB. fieldistorC. MOS-FETD. IGFETANSWER: A

250. Which type of FET has the lowest input resistance?A. JFETB. MOS-FETC. IGFETD. VMOSFETANSWER: A

251. In order to increase further the input resistance of a FET, its gate is insulated. An example of this type is theA. fieldistorB. JFETC. MOS-FETD. A and B a

�ove

ANSWER: C

252. What is the insulator used in most MOS-FET?A. CO2B. SiO2C. micaD. plasticANSWER: B

253. An n-channel JFET has a drain-source saturation current IDSS = 10 mA and a gate-source pinch-off voltage Vp = -4 V. If the applied reverse gate-source voltage VGS = 2 V, calculate the drain current ID.A. 2.5 mAB. 5.0 mAC. 10.0 mAD. 22.5 mAANSWER: A

254. Base from Shockley’s equation of a JFET, what is the drain current when the applied voltage VGS is exactly equal to the pinch-off voltage Vp?A. IDSSB. maximumC. minimumD. zeroANSWER: D255. The transconductance of a JFET is defined asA. dID/dVGSB. dVGS/dIDC. dIDSS/dVGSD. dID/dVpANSWER: A

256. A field-effect transistor in which the gate electrode is not a pn junction (as in the junction field-effect transistor)

�ut a thin metal film insulated fro

m the semiconductor channel �y a thin oxide film.

A. MOSFET (enhancement type)B. MOSFET (depletion type)C. IGFETD. all of the a

�ove

ANSWER: D

257. In MOSFET, it is the foundation upon which the device will �e constructed a

nd is formed from a silicon �ase

A. su�strate

B. sla�

C. sourceD.

�ase

ANSWER: A

258. A type of MOSFET wherein originally there is no channel �etween the drain a

nd the sourceA. depletion typeB. enhancement typeC.

�reak type

D. insulated typeANSWER: B

259. What type of MOSFET whose channel is originally thick �ut narrows as the pr

oper gate �ias is applied?

A. enhancementB. depletionC. transverseD. all of the a

�ove

ANSWER: B

260. The amount of voltage needed at the gate-source terminal for an enhancement type MOSFET so that a channel can

�e formed for the current to flow.

A. “ON” voltageB. pinch-off voltage

C. threshold voltageD. trigger voltageANSWER: C

261. To switch off the depletion type MOSFET, the channel should �e depleted. De

pletion of the channel is done �y applying enough voltage across the gate-source

terminal. What do you call this voltage?A. pinch-off voltageB. trigger voltageC. holding voltageD. threshold voltageANSWER: A

262. The su�strate of a MOSFET is usually connected internally to

A. sourceB. gateC. drainD. channelANSWER: A

263. In an n-channel enhancement type MOSFET, the gate voltage should �e _______

_ with respect to the source in order to produce or enhance a channel.A. the sameB. positiveC. negativeD. either positive or negativeANSWER: B

264. To deplete a channel from a p-channel IGFET depletion type, the gate voltage should

�e ________ with respect to the source.

A. the sameB. positiveC. negativeD. either positive or negative as long as it is greaterANSWER: B

265. The su�strate used in a p-channel IGFET enhancement type

A. n -type materialB. n+ -type materialC. p -type materialD. p+ -type materialANSWER: A

266. The �ase material of a MOSFET which extends as an additional terminal

A. source (S)B. channel (C)C. drain (D)D. su

�strate (SS)

ANSWER: D

267. Which FET that has a su�strate?

A. MOSFET enhancement typeB. IGFETC. MOSFET depletion typeD. all of the a

�ove

ANSWER: D

268. What is the difference �etween a JFET and a MOSFET?

A. The gate of a MOSFET is insulated.B. MOSFET uses a su

�strate in its construction.

C. MOSFET can work in �oth forward and reverse gate-source voltages.

D. all of the a�ove

ANSWER: D

269. Calculate the transconductance of a p-channel MOSFET enhancement type if the gate-source voltage VGS = -8 V, threshold voltage VT = -4 and a constant k = 0.3 mA/V2.A. 1.2 mSB. 2.4 mSC. 3.6 mSD. 7.2 mSANSWER: B

270. One draw�ack of JFET devices is the strong dependence of the devices’ paramet

ers on the channel geometry. Which parameter is an example of this?A. drain saturation current (IDSS)B. pinch-off voltage (VP)C. transconductance (gm)D. all of the a

�ove

ANSWER: D

271. JFET cutoff frequency is dependent on channel length �y a factor of

A. 1/LB. 1/L2C. 1/L3D. 1/L4ANSWER: B

272. Which FET operates as close as BJT in terms of switching?A. JFETB. MOSFET depletion typeC. MOSFET enhancement typeD. IGFETANSWER: C

273. Generally, MOSFET has low power handling capa�ility than BJT. To increase M

OSFET power, the channel should �e made

A. narrow and longB. narrow and shortC. wide and longD. wide and shortANSWER: D

274. Which FET has a wide and short effective channel?A. JFETB. MOSFETC. IGFETD. V-MOSFETANSWER: D

275. A type of FET wherein the channel is formed in the vertical direction rather than horizontalA. JFETB. MOSFETC. IGFETD. V-MOSFETANSWER: D

276. Advantage or advantages of V-MOS over BJTA. No stored charge and therefore faster in switching action.

B. A negative temperature dependence of output current which eliminates thermal runaway.C. High input impedance and therefore high current gain.D. all of the a

�ove

ANSWER: D

277. In general, which of the transistors is particularly more useful in integrated-circuit (IC) chips?A. BJTsB. FETsC. UJTsD. all of the a

�ove

ANSWER: B

278. A monolithic semiconductor-amplifying device in which a high-impedance GATE electrode controls the flow of current carriers through a thin

�ar of semicondu

ctor called the CHANNEL. Ohmic connections made to the ends of the channel constitute SOURCE and DRAIN electrodes.A. BJTB. UJTC. FETD. UPTANSWER: C

279. A junction field effect transistor has a drain saturation current of 10 mA and a pinch-off voltage of -4 V. Calculate the maximum transconductance.A. 2.5 mSB. 5.0 mSC. 25.0 mSD. 50.0 mSANSWER: B280. In semiconductor application, which of the following statement is not true?A. An ohmmeter test across the

�ase-collector terminal of a transistor should sh

ow low resistance in one polarity and high resistance in the opposite polarity.B. A triac is a

�idirectional device.

C. An ohmmeter test across a diode shows low resistance in one polarity and high resistance in the opposite polarity.D. An ohmmeter test across the

�ase-collector of a transistor should show low re

sistance for �oth polarities.

ANSWER: D

Test 4 – Amplifiers

1. What do you call an amplifier which has an output current flowing during the whole input current cycle? A. class AB amplifier B. class B amplifier C. class A amplifier D. class C amplifier ANSWER: C

2. Class A amplifier can �e �uilt from what transistor configuration?

A. common �ase

B. common emitter C. common collector D. all of the a

�ove

ANSWER: D 3. If a transistor amplifier provides a 360° output signal, it is classified as A. class A

B. class B C. class C D. class D

ANSWER: A 4. An amplifier that delivers an output signal of 180° only. A. class A B. class B C. class AB D. class D

ANSWER: B 5. A class of amplifiers wherein the output signal swings more than 180°

�ut less

than 360°. A. class A B. class B C. class C D. class AB ANSWER: D 6. What is the distinguishing feature of a class C amplifier? A. Output is present for less than 180 degrees of the input signal cycle B. Output is present for the entire signal cycle C. Output is present for exactly 180 degrees of the input signal cycle D. Output is present for more than 180 degrees

�ut less than 60 degrees of the i

nput signal cycle

ANSWER: A 7. A full 360° sine-wave signal is applied as an input to an unknown class of amplifier, if the output delivers only a pulse of less than 180°, of what class does this amplifier

�elongs?

A. class AB B. class B C. class C D. class D

ANSWER: C 8. Which class of amplifiers that is intended for pulse operation? A. class B B. class C C. class D D. class S

ANSWER: C 9. How do you classify an amplifier used to amplify either amplitude modulated (AM) or frequency modulated (FM) signals? A. class C B. class BC C. class D D. class S

ANSWER: D 10. Which class of amplifiers that has the highest efficiency? A. class A B. class B C. class C D. class D

ANSWER: D 11. What is the efficiency of a series-fed class A amplifier? A. 25%

B. 50% C. 78.5% D. a

�ove 90%

ANSWER: A 12. A class A amplifier has an efficiency of only 25%,

�ut this can

�e increased

if the output is coupled with a transformer. Up to how much is its efficiency will reach due to coupling? A. 36.5% B. 50% C. 68.5% D. 78.5%

ANSWER: B 13. Class B amplifiers deliver an output signal of 180° and have a maximum efficiency of A. 50% B. 68.5% C. 78.55 D. a

�ove 90%

ANSWER: C 14. Transistorized class C power amplifiers will usually have an efficiency of A. 25% B. 33% C. 50% D. 78.5%

ANSWER: B 15. For pulse-amplification, class D amplifier is mostly used. How efficient is a class D amplifier? A. a

�out 25% efficient

B. less efficient than class B C. more efficient than class A

�ut less efficient than class B

D. its efficiency reaches over 90%

ANSWER: D 16. An amplifier of class AB means its output signal is

�etween the output of cl

ass B and A, such that it varies from 180° (class B) to 360° (class A). How a�out it

s efficiency? A. Efficiency of class AB is in

�etween the efficiency of class A and B, that is

from 25% - 78.5%. B. It is always as efficient as class A (25%). C. It is always as efficient as class B (78.5%) D. The efficiency of class AB is the average of the efficiencies of

�oth class A

and class B (25% + 78.5%)/2 = 51.75%

ANSWER: A 17. Among the given amplifiers

�elow, which is the most efficient?

A. class A (series-fed) B. class A (transformer-coupled) C. class A (directly-coupled) D. class A (capacitor-coupled) ANSWER: B 18. In order to have the

�est efficiency and sta

�ility, where at the loadline sh

ould a solid state power amplifier �e operated?

A. Just �elow the saturation point

B. At 1.414 times the saturation point C. Just a

�ove the saturation point

D. At the saturation point

ANSWER: A 19. In most transistor class A amplifiers, the quiescent point is set at A. near saturation B. near cutoff C.

�elow cutoff

D. at the center

ANSWER: D 20. For a class B amplifier, the operating point or Q-point is set at A. the top of the load line B. saturation C. the center D. cutoff

ANSWER: D 21. The Q-pint for class A amplifier is at the active region, while for class B it is at cutoff region, how a

�out for class AB?

A. it is slightly �elow saturation

B. it is slightly a�ove cutoff

C. it is slightly a�ove saturation

D. it is at the saturation region

ANSWER: B 22. Where does the Q-point of a class C amplifier positioned? A. at saturation region B. at active region C. at cutoff region D.

�elow cutoff region

ANSWER: D 23. The Q-point of a class D amplifier can

�e set or positioned at what region i

n the load line? A.

�elow saturation

B. a�ove cutoff

C. at cutoff D. any of the a

�ove

ANSWER: D 24. Which of the amplifiers given

�elow that is considered as non-linear?

A. class A B. class B C. class AB D. class C

ANSWER: D 25. Which amplifiers can

�e used for linear amplification?

A. class A B. class B C. class C D. class A or B

ANSWER: D 26. What do you call an amplifier that is

�iased to class C

�ut modulates over t

he same portion of the curve as if it were �iased to class B?

A. class S B. class D C. class AB D. class BC

ANSWER: D 27. Two class B amplifiers connected such that one amplifies the positive cycle and the other amplifies the remaining negative cycle. Both output signals are then coupled

�y a transformer to the load.

A. transformer-coupled push –pull amplifier B. complementary-symmetry amplifier C. quasi-complementary push-pull amplifier D. transformer-coupled class A amplifier

ANSWER: A 28. A push-pull amplifier that uses npn and pnp transistors to amplify the positive and negative cycles respectively. A. transformer-coupled push –pull amplifier B. complementary-symmetry amplifier C. quasi-complementary push-pull amplifier D. transformer-coupled class A amplifier

ANSWER: B 29. A push-pull amplifier that uses either npn or pnp as its final stage. The circuit configuration looks like the complementary-symmetry. A. transformer-coupled push –pull amplifier B. complementary-symmetry amplifier C. quasi-complementary push-pull amplifier D. feed-

�ack pair amplifier

ANSWER: C 30. Amplifiers conversion efficiency are calculated using what formula? A. ac-power/dc-power B. ac-power/dissipated power C. dc-power/ac-power D. A or B are correct ANSWER: D 31. Basically, which class of amplifiers has the least distortion? A. class A B. class B C. class C D. class D

ANSWER: A 32. A type of distortion wherein the output signal does not have the desired linear relation to the input. A. linear distortion B. nonlinear distortion C. cross-over distortion D. all of the a

�ove

ANSWER: B 33. Distortion that is due to the ina

�ility of an amplifier to amplify equally w

ell all the frequencies present at the input signal. A. nonlinear distortion B. amplitude distortion C. harmonic distortion D. cross-over distortion

ANSWER: B 34. A nonlinear distortion in which the output consists of undesired harmonic frequencies of the input signal. A. amplitude distortion B. frequency distortion C. cross-over distortion

D. harmonic distortion

ANSWER: D 35. Calculate the 2nd harmonic distortion for an output signal having a fundamental amplitude of 3V and a 2nd harmonic amplitude of 0.3V. A. 1.0% B. 10% C. 23.33% D. 43.33%

ANSWER: B 36. An amplifier has the following percent harmonic distortions; D2=10%, D3=5% and D4=1%. What is the amplifier % THD? A. 5.33% B. 11.22% C. 16.0% D. 22.11%

ANSWER: B 37. Which of the following refers to the gain of a circuit? A. Input quantity of an amplifier divided

�y the output quantity.

B. The difference �etween the input voltage and the output voltage of a circuit.

C. The ratio of the output quantity to input quantity of an amplifier. D. The total increase in output quality over the input quantity of an amplifier.

ANSWER: C 38. The overall gain of an amplifier in cascade is A. the sum B. the average of each C. the product D. 100% the sum

ANSWER: C 39. If three amplifiers with a gain of 8 each are in cascade, how much is the overall gain? A. 72 B. 24 C. 512 D. 8

ANSWER: C 40. A multistage transistor amplifier arranged in a conventional series manner, the output of one stage is forward-coupled to the next stage. A. cascaded amplifier B. cascoded amplifier C. darlington configuration D. feed-

�ack pair configuration

ANSWER: A 41. A direct-coupled two-stage transistor configuration wherein the output of the firs transistor is directly coupled and amplified

�y the second transistor. Th

is configuration gives a very high current gain. A. cascade configuration B. cascode configuration C. darlington configuration D. feed-

�ack pair

ANSWER: C

42. A two-stage transistor amplifier in which the output collector of the first stage provides input to the emitter of the second stage. The final output is then taken from the collector of the second stage. A. cascade configuration B. cascode configuration C. quasi-complementary D. complementary amplifier

ANSWER: B 43. Famous transistor amplifier configuration designed to eliminate the so called Miller effect. A. cascode amplifier B. darlington amplifier C. differential amplifier D. complementary-symmetry

ANSWER: A 44. What are the transistor configurations used in a cascade amplifier? A. common-

�ase and common-emitter

B. common-�ase and common-collector

C. common-collector and common-emitter D. common-emitter and common-

�ase

ANSWER: D 45. Transistor configuration known to have a super-

�eta (β2).

A. cascade B. cascode C. darlington D. differential

ANSWER: C 46. What is the approximate threshold voltage

�etween the

�ase-emitter junction

of a silicon darlington transistor? A. 0.3 V B. 0.6 V C. 1.6 V D. 3.0 V

ANSWER: C 47. Transistor arrangement that operates like a darlington

�ut uses a com

�inatio

n of pnp and npn transistors instead of �oth npn.

A. differential B. common C. cascode D. feed

�ack pair

ANSWER: D 48. An amplifier

�asically constructed from two transistors and whose output is

proportional to the difference �etween the voltages applied to its two inputs.

A. differential amplifier B. cascode amplifier C. complementary amplifier D. quasi-complementary amplifier

ANSWER: A 49. An amplifier having high direct-current sta

�ility and high immunity to oscil

lation, this is initially used to perform analog-computer functions such as summing and integrating. A. operational amplifier (op-amp) B. parametric amplifier (par-amp)

C. instrumentation amplifier D. DC-amplifier

ANSWER: A 50. One of the most versatile and widely used electronic device in linear applications. A. SCR B. FET C. UJT D. op-amp

ANSWER: D 51. It is a very high-gain differential amplifier with very high input impedance and very low output impedance. A. par-amp B. op-amp C. differential amp D. complementary amp

ANSWER: B 52. What are the possi

�le applications of operational amplifiers (op-amps)?

A. ac and dc-amplifiers B. oscillators and signal conditioning C. voltage-level detectors and comparators D. all of the a

�ove

ANSWER: D 53. An operational amplifier must have at least how many usa

�le terminals?

A. 3 terminals B. 5 terminals C. 8 terminals D. 14 terminals

ANSWER: B 54. The circuit at the input stage of operational amplifiers A. differential amplifier B. cascaded amplifier C. current mirror D. complementary amplifier

ANSWER: A 55. An amplifier whose output is proportional to the difference

�etween the volt

ages applied to its two inputs. A. differential amplifier B. differencing C. delta amp D. cascode-amp ANSWER: A 56. In op-amps functional

�lock diagram, what follows the differential amplifier

? A. cascode-amplifier B. complementary amplifier C. level shifter D. high gain amplifier

ANSWER: D 57. A good op-amp has a A. very high input resistance B. very low input resistance C. very high output resistance

D. very low CMRR

ANSWER: A 58. Ideally, op-amps have infinite input resistance and ________ output resistance. A. infinite B. zero C. varia

�le

D. a highly sta�ilized

ANSWER: B 59. How does the input of an op-amp made high? A.

�y using super

�eta transistor at the input differential stage

B. �y using FETs at the input differential stage

C. �y connecting a very high resistance in series with the input differential st

age D. A and B a

�ove

ANSWER: D 60. What type of amplifier commonly used at the output stage of op-amps? A. differential amplifier B. cascade-amplifier C. complementary amplifier D. darlington stage amplifier

ANSWER: C 61. The transistor configuration used at the output complementary stage of most op-amps A. cascode configuration B. common emitter C. common collector D. common

�ase

ANSWER: C 62. Why do most op-amps use a common collector at the output stage? A. to have a higher output power B. to have a

�etter frequency response

C. to have a low harmonic distortion D. to have a very low output resistance

ANSWER: D 63. The stage followed

�y the output complementary in op-amps functional

�lock d

iagram. A. level shifter B. phase shifter C. current mirror D. polarizer

ANSWER: A 64. What is the purpose of a level shifter in op-amps? A. to set and/or adjust the output voltage to zero when the input signal is zero B. to set and/or adjust the input offset voltage to zero C. to shift the input offset current to zero D. all of the a

�ove

ANSWER: A 65. Primarily, op-amps are operated with

�ipolar power supply, however, we can a

lso use single polarity power supply �y

A. generating a reference voltage a�ove ground.

B. “floating” the negative supply terminal (V-) of the op-amp. C. simply connecting the negative supply terminal (V-) of the op-amp to ground. D. isolating the negative supply terminal (V-)

�y a capacitor.

ANSWER: A 66. Op-amps have two input terminals namely, the inverting (-) and non-inverting (+) inputs. What is the significance of its name? A. If a sine-wave is applied to the inverting (-) input, the output will

�e inve

rted or shifted �y 180°, while if applied to the non-inverting (+) there will

�e n

o phase shift at the output. B. If pulses are applied to the inverting (-) input, the positive pulse

�ecomes

negative at the output and vice versa, while if applied at the non-inverting (+) there will

�e no reversal of the pulse at the output.

C. In dc amplifier applications, increasing input at the inverting (-) terminal causes the output to decrease and vice versa, while at the non-inverting (+) input, the output magnitude goes with the input. D. all of these are correct

ANSWER: D 67. When the same signal is applied to

�oth inverting and non-inverting input te

rminals of an ideal op-amp, the output voltage would �e

A. zero (0) V B. +VSAT C. –VSAT D. offset voltage

ANSWER: A 68. The operating mode of an op-amp, when

�oth inputs are tied together or when

the input signal is common to �oth inputs.

A. differential mode B. rejection mode C. dou

�le-ended mode

D. common mode

ANSWER: D 69. What do you call of the gain of an op-amp if operated in common mode input? A. differential gain B. common gain C. dou

�le-ended gain

D. rejection gain

ANSWER: B 70. When one input of the op-amp is connected to ground and the other is to the signal source, its operation is called A. single-ended output B. dou

�le-ended output

C. single-ended input D. dou

�le-ended input

ANSWER: C 71. If op-amps are operated in differential mode, its gain is technically termed as A. common-mode differential gain B. differential gain C. open-loop gain D. closed-loop gain

ANSWER: B 72. In op-amps, which gain is the highest? A. common-mode gain

B. differential gain C. closed-loop gain D. open-loop gain

ANSWER: D 73. The ratio of the differential gain and common gain of an op-amp A. differential-common mode ratio B. common-mode ratio C. differential-mode rejection ratio D. common-mode rejection ratio

ANSWER: D 74. An operational amplifier has a common-mode voltage gain of 10 and a differential-mode voltage gain of 20,000, calculate its common-mode rejection ratio (CMRR).

A. 200 B. 2,000 C. 20,000 D. 200,000

ANSWER: B 75. Calculate the CMRR of an op-amp having a common-mode gain of 10 and a differential-mode gain of 100,000. A. 1000 dB B. 100 dB C. 80 dB D. 40 dB

ANSWER: C 76. The non-inverting and inverting inputs of an op-amp have an input voltage of 1.5 mV and 1.0 mV, respectively. If the op-amp has a common-mode voltage gain of 10 and a differential-mode gain of 10,000, what is its output voltage? A. 5.0 V B. 5.0125 mV C. 5.0125 V D. 25.0125 V

ANSWER: C 77. What is the maximum output voltage swing of an op-amp? A. +V to -V (supply voltage) B. +VSAT to -VSAT C. +½V to -½V D. depends on the input signal

ANSWER: B 78. The μA741 op-amp has a CMRR of 90dB and a differential-mode voltage amplification of 200,000.What is the op-amp’s common-mode voltage gain? A. 31,622.778 B. 632.40 C. 6.324 D. 0.158

ANSWER: C 79. The current needed at the input of an op-amp to operate it normally A. input bias current B. input offset current C. input threshold current D. input holding current

ANSWER: A 80. Ideal op-amp requires no input current, but real op-amp needs a very small input current called input bias current. At both inputs, the bias currents have a slight difference. What do you call this difference? A. differential input current B. differential bias C. input offset difference D. input offset current

ANSWER: D 81. The change in input offset current due to temperature change A. delta input offset current B. slew rate C. input offset current drift D. PSRR

ANSWER: C 82. The reason why a slight difference between the input bias current occurs in op-amps is due to the unsymmetrical circuit component parameters. This unsymmetrical condition also produces a difference in input voltage called what? A. drift voltage B. differential voltage C. input offset voltage D. input threshold voltage

ANSWER: C 83. As electronic circuit operates, its operating temperature changes which causes device parameters to change. In op-amps, what do you call the change in input offset voltage due to the change in temperature? A. input differential drift B. input offset voltage drift C. slew rate D. PSRR

ANSWER: B 84. It is known through experiment that the input bias currents at the non-inverting (IB+) and inverting (IB-) inputs of a certain op-amp is 100 nA and 80 nA, respectively. Determine the op-amp’s input offset current. A. -20 nA B. 20 nA C. 90 nA D. 180 nA

ANSWER: B 85. Ideally, the output voltage of an op-amp is zero when there is no input signal, however, in practical circuits, a small output voltage appears, this voltage is known as A. minimum output voltage B. pinch-off voltage C. output offset voltage D. saturation voltage

ANSWER: C 86. The output offset voltage of an op-amp is (are) due to A. input offset current B. input offset voltage C. voltage and current drift D. A and B above

ANSWER: D

87. Calculate the output offset voltage of an inverting amplifier using op-amp with an input offset current of 10 nA. The circuit is having an input resistance of 10 kΩ and a feedback resistance of 100 kΩ. A. 0.1 mV B. 1.0 mV C. 10.0 mV D. 100.0 mV

ANSWER: B 88. An op-amp inverting amplifier uses a feedback resistor of 100 kΩ and input resistor of 10 kΩ. If the op-amps input offset voltage is 2.0 mV, approximate the amplifier output offset voltage due to this input offset voltage. A. 10 mV B. 11 mV C. 20 mV D. 22 mV

ANSWER: D 89. The output offset voltage of an op-amp is due to the input offset current and voltage. If 1 mV is due to the input offset current and 22 mV due to the input offset voltage, what is the total output offset voltage of the op-amp? A. 11.5 mV B. 22 mV C. 23 mV D. 45 mV

ANSWER: C 90. How will you minimize the output offset voltage due to the input offset current of an op-amp? A. by installing a bias-current-compensating resistor B. by increasing the value of the feedback resistor C. by decreasing the value of the input resistor D. B and C above

ANSWER: A 91. What is a bias-current compensating resistor in op-amp circuits? A. A resistor used to reduce the undesired output offset voltage due to the input offset current. B. A resistor connected between the non-inverting terminal and ground. C. A resistor used to balance both input bias currents and therefore eliminates the input offset current. D. all of these

ANSWER: D 92. The approximate value of the bias-current compensating resistor in op-amp circuits is A. equal to the feedback resistor B. equal to the input resistor C. equal to the series combination of the input and feedback resistors D. equal to the parallel combination of the input and feedback resistors

ANSWER: D 93. In op-amp analysis, the input offset voltage is represented by A. a battery B. a signal generator C. Thevenin’s voltage source D. Norton’s current source

ANSWER: A 94. The battery representing the input offset voltage in op-amp circuit analysis

is connected where? A. between the inverting and ground terminal B. between the non-inverting and ground terminal C. between the inverting and non-inverting terminal D. either B and C above

ANSWER: B 95. What is the effect of the input offset voltage to the output voltage if the op-amp has no feedback element? A. causes the output to be always at cutoff B. causes the output to saturate towards positive C. causes the output to saturate towards negative D. causes the output to saturate either towards positive or negative

ANSWER: D 96. How can we minimize the effect of the input offset current and input offset voltage at the output offset voltage? A. by making the feedback resistance small B. by making the feedback resistance large C. by making the input resistance small D. by making the input resistance large

ANSWER: A 97. An op-amp is wired as an inverting amplifier with an input and feedback resistances of 1 kΩ and 100 kΩ, respectively. When the input signal is set to zero, the output was found to have an offset voltage of 101 mV. Calculate the input offset voltage. A. 0.01 mV B. 0.1 mV C. 1.0 mV D. 10.0 mV

ANSWER: C 98. What is the most effective way of minimizing the output offset voltage of an op-amp? A. by reducing the value of the feedback resistor B. by increasing the value of the input resistor C. by a capacitor-compensation technique D. by properly using and adjusting the offset-null terminals

ANSWER: D 99. What cause(s) the well-adjusted output offset voltage of op-amps to change? A. change in operating temperature B. component aging C. variations in supply voltage D. all of the above

ANSWER: D 100. Which op-amp parameter(s) that normally affects its small signal dc-amplification performance? A. input bias current B. input offset voltage C. input offset current D. all of the above

ANSWER: D 101. Op-amp parameter(s) that is important in large signal dc-amplification. A. input offset voltage B. input offset current C. slew rate

D. all of the above

ANSWER: C 102. In large signal dc-amplifiers using op-amp, which parameter has the least effect on its performance? A. drift B. slew rate C. input offset voltage D. input offset current

ANSWER: A 103. For ac-amplifiers using op-amps what parameters can affect its performance. A. input offset current and voltage B. input bias current and voltage C. drift and slew rate D. slew rate and frequency response

ANSWER: D 104. If an op-amp is used to amplify small ac-signals, what parameter you should greatly consider to ensure better performance? A. input bias current B. drift C. frequency response D. slew rate

ANSWER: C 105. What do we mean by internally compensated op-amps? A. Op-amps with internal frequency compensation capacitor to prevent oscillation. B. Op-amps with an internal compensating resistor to make the output offset voltage zero. C. Op-amps with internal coupling capacitor to block dc-voltages and allows ac-voltages to pass. D. Op-amps with internal active components to make its gain constant at the entire operating frequency.

ANSWER: A 106. The frequency at which the open-loop gain of an op-amp is 0.707 times its value at very low frequency A. threshold frequency B. break frequency C. minimum frequency D. operating frequency

ANSWER: B 107. What will happen to the voltage gain of op-amp when its operating frequency is increased? A. also increases B. increases exponentially C. will decrease D. decreases exponentially

ANSWER: C 108. The reduction of op-amps gain due to increasing operating frequency. A. Cutoff B. roll-off C. diminishing factor D. reduction step

ANSWER: B 109. What do we mean by a 20 dB/decade roll-off? A. a gain reduction by a factor of 10 per decade B. a gain reduction by a factor of 20 per decade C. a gain reduction by a factor of 10 per 10 Hz increased in frequency D. a gain reduction by a factor of 20 per 10 Hz increased in frequency ANSWER: A 110. A reduction of op-amp’s voltage gain by a factor of two each time the frequency doubles. A. 2 dB/octave B. 2 dB/decade C. 6 dB/octave D. 6 dB/decade

ANSWER: C 111. Frequency at which the voltage gain of op-amp reduces to unity. A. unity-gain frequency B. cutoff frequency C. bandwidth point D. unity-gain bandwidth product

ANSWER: D 112. The low and high cutoff frequencies of an amplifier is also called A. corner frequencies B. 0.707 frequencies C. 3-dB frequencies D. all of these are correct

ANSWER: D 113. Calculate the cutoff frequency (fc)of an op-amp having a unity-gain bandwidth product B1 = 1 MHz and a open-loop voltage gain AOL = 100,000. A. 10 Hz B. 20 Hz C. 100 Hz D. 200 Hz

ANSWER: A 114. An op-amp has a specified transient response rise time of 0.3 μs, calculate its unity-gain bandwidth. A. 0.857 MHz B. 1.0 MHz C. 1.167 MHz D. 2.334 MHz

ANSWER: C 115. Rise time is defined as the time required for the output voltage to rise from _______ to ________ of its final value. A. 0% - 100% B. 1% - 99% C. 5% - 95% D. 10% - 90%

ANSWER: D 116. The maximum output voltage rate of change of an op-amp. A. rise time B. maximum voltage swing C. differential rate D. slew rate

ANSWER: D

117. Factor(s) or parameter(s) that determine(s) the op-amps maximum operating temperature A. PSRR B. slew rate C. unity-gain bandwidth product D. B and C above

ANSWER: D 118. What is the maximum signal frequency that can be used in an op-amp having a specified slew rate of 0.5 V/μsec? The maximum output voltage desired is 5 V. A. 16 kHz B. 32 kHz C. 100 kHz D. 1 MHz

ANSWER: A 119. What must be the slew rate of an op-amp to be used in order to provide an undistorted output voltage of .10 V ac a frequency of 100,000 rad/sec? A. 0.1 V/μsec B. 0.5 V/μsec C. 1.0 V/μsec D. 6.28 V/μsec

ANSWER: C 120. When an op-amp is used as a comparator, the output voltage would be +VSAT if A. V+ > V- B. V- > V+ C. V- = V+ D. V- and V+ are both zero

ANSWER: A 121. Two comparators using op-amps, configured such that it can detect voltage levels within a certain range of values rather than simply comparing whether a voltage is above or below a certain reference. A. analog comparator B. regenerative comparator C. parallel comparator D. window comparator

ANSWER: D 122. What gain is significant when an op-amp is used as a voltage comparator? A. open-loop gain B. common gain C. differential closed loop gain D. closed loop gain ANSWER: A 123. An op-amp zero-crossing detector without hysteresis, A. uses a resistor as its feedback element B. uses a capacitor as its feedback element C. uses an inductor as its feedback element D. has no feedback

ANSWER: D 124. The feedback element of a differentiator constructed from op-amp is A. a resistor B. an inductor C. a capacitor D. an RC network

ANSWER: A 125. An active integrator uses an op-amp, what is its feedback element? A. Resistor B. capacitor C. inductor D. RC network

ANSWER: B 126. The voltage gain of an op-amp voltage follower. A. unity B. Rf/Ri C. 1 + Rf/Ri D. depends on the type of op-amp

ANSWER: A 127. Calculate the closed-loop voltage gain of an inverting amplifier having a feedback and an input resistance of 100 kΩ and 10 kΩ, respectively. A. 10 B. 11 C. 100 D. 110

ANSWER: A 128. The gain of an inverting amplifier is determined by the ratio of the feedback and input resistors (Rf/Ri), meaning we can select any value of resistors as long as its ratio is the same. What op-amp parameter that helps us determine the appropriate values of these resistors? A. CMRR B. PSRR C. SR D. input bias current

ANSWER: D 129. What is the noise gain of op-amps? A. equal to the open loop gain B. Rf/Ri C. 1 + Rf/Ri D. equal to the common gain

ANSWER: C 130. A unity-gain summing amplifier has three inputs, V1 = 1.0 mV, V2 = 1.5 mV, and V3 = 2.5 mV, calculate the total output voltage. A. 2.5 mV B. 3.5 mV C. 4.0 mV D. 5.0 mV

ANSWER: D 131. The random voltage at the output of an op-amp which could occupy the entire bandwidth. A. noise B. hash C. interference D. all of the above

ANSWER: D 132. Which of the following of the resistor combinations that provides lesser noise in op-amp circuits? A. Make both the feedback and input resistances as large as possible B. Make the feedback as large as possible, while the input as low as possible.

C. Make the feedback as low as possible, while the input as large as possible. D. Make the feedback and input resistances as small as possible.

ANSWER: D 133. In most ac-amplifiers using op-amps, the feedback resistor is shunted with a very small capacitance, what is its purpose? A. to prevent oscillation B. to improve stability C. to minimize high frequency noise D. to compensate for high frequency loss

ANSWER: C 134. Approximate the noise gain of an inverting adder using op-amps if it has five inputs. A. unity (1) B. two (2) C. four (4) D. six (6)

ANSWER: D 135. Op-amps with internal frequency compensation are very stable with respect to signal frequencies. However, the trade-off for frequency stability is (are) A. limited small-signal bandwidth B. slow slew rate C. limited open-loop frequency response D. all of these

ANSWER: D 136. What do we mean by externally compensated op-amps? A. op-amps with frequency-compensation terminals B. op-amps with provision to externally compensate for frequency stability C. op-amps whose gain is externally compensated D. A and B above

ANSWER: D 137. What is true about the external frequency-compensation capacitor? A. the higher its value, the wider is its bandwidth B. the lower its value, the wider is its bandwidth C. the higher its value, the faster its slew rate D. A and C above

ANSWER: B 138. Typical value of the external frequency-compensating capacitor of op-amps. A. 3 - 30 nF B. 30 - 300 nF C. 0.3 - 3.0 μF D. 3.0 - 30 μF

ANSWER: D 139. What do we mean by a general-purpose op-amps? A. op-amps with limited unity-gain bandwidth up to approximately 1 MHz B. op-amps with slew rate about 0.5 V/μsec C. op-amps that has unlimited application D. A and B above

ANSWER: D 140. Op-amps designed to operate at high slew rate, about 2000 V/μsec and at high frequencies, more than 50 MHz. A. general purpose op-amps B. high power op-amps

C. high-stability op-amps D. high-frequency, high-slew rate op-amps

ANSWER: D 141. Generally, where does hybrid op-amps found its application? A. for high-output voltage B. for high-output current C. for high-frequency D. A and B above ANSWER: D 142. The magnitude of the op-amps input offset voltage before it can be classified as a low-input offset voltage op-amp A. 0.2 mV B. 2.0 mV C. 2.5 mV D. 5.0 mV

ANSWER: A 143. Op-amps whose internal transistor biasing can be controlled externally are categorize as A. general purpose op-amps B. programmable op-amps C. variable op-amps D. externally compensated op-amps

ANSWER: B 144. What op-amp parameter(s) that can be governed by the bias control in a programmable op-amp? A. open-loop gain and slew rate B. unity-gain bandwidth C. input bias current D. all of the above

ANSWER: D 145. The most popular op-amp packages are the metal can, 8-pin DIP, and the SMT. Which of these corresponds to TO-99? A. metal can B. 8-pin DIP C. SMT D. all of the above

ANSWER: A 146. Dual-in-line or DIL package is designated as A. TO-99 B. TO-91 C. TO-116 D. TO-220

ANSWER: C 147. For high density ICs involving many op-amps, what packaging is suitable? A. metal can B. 14-pin DIL C. SMT D. flat-pack

ANSWER: C 148. Example(s) of surface-mounted technology (SMT) devices. A. PLCCs B. SOICs C. LCCCs

D. all of the above ANSWER: D 149. Which condition must exist for a circuit to oscillate? A. It must have a negative feedback sufficient to cancel the input B. It must have a gain of less than 1 C. It must have a positive feedback sufficient to overcome losses D. It must be neutralized

ANSWER: C 150. Which of the following is not an essential part of an oscillator? A. Source of energy that supply the losses in tank circuit. B. A resistor IC combination circuit. C. Resonant circuit consist of inductance and capacitance. D. Regenerative feedback circuit.

ANSWER: B 151. Circuits that produces alternating or pulsating current or voltage. A. Damper B. Generator C. oscillator D. mixer

ANSWER: C 152. What do you call the oscillator circuit that uses a tapped coli in the tuned circuit? A. Pierce B. Colpitts C. Hartley D. Ultraudion

ANSWER: C 153. What determines the resonant frequency of a crystal? A. external components B. the temperature of the crystal C. the size and thickness of the crystal material D. the hermitic seal

ANSWER: C 154. Type of oscillator whose frequency is dependent on the charge and discharge of RC networks. A. Hartley oscillator B. Copitts oscillator C. Relaxation oscillator D. Klystron oscillator

ANSWER: C 155. A microwave oscillator A. Hartley oscillator B. Copitts oscillator C. Relaxation oscillator D. Klystron oscillator

ANSWER: D 156. A self-excited oscillator in which the tank is divided into input and feedback portions by a capacitive voltage divider. A. Hartley capacitor B. Copitts oscillator C. Relaxation oscillator D. Klystron oscillator

ANSWER: B 157. A self-excited oscillator in which the tank is divided into input and feedback portions by an inductive voltage divider or a tapped coil. A. Hartley oscillator B. Copitts oscillator C. Relaxation oscillator D. Klystron oscillator

ANSWER: A 158. A circuit usually containing two transistors or tubes in an RC-coupled amplifier, the two active devices switch each other alternately on and off. A. Multivibrator B. Signal generator C. Oscillator D. Thyristor

ANSWER: A 159. A multivibrator that generates one output pulse for each input trigger pulse. A. monostable B. astable C. bistable D. tristate

ANSWER: A 160. Monostable multivibrator is also known as A. one shot B. single shot C. direct shot D. one shot or single shot

ANSWER: D 161. What determines the pulse time in a monostable multivibrator? A. resistor combinations B. capacitor combinations C. inductor combinations D. resistor and capacitor combinations

ANSWER: D 162. A multivibrator having two stable state A. monostable B. bistable C. astable D. unstable

ANSWER: B 163. Is also known as Eccles/Jordan circuit A. Monostable multivibrator B. bistable multivibrator C. astable multivibrator D. unstable multivibrator

ANSWER: B 164. Flip-flop is actually a _______ multivibrator. A. Monostable B. bistable C. astable D. unstable ANSWER: B 165. Considered as a free-running multivibrator

A. monostable B. bistable C. astable D. unstable ANSWER: C

Test 5 – Energy Conversion 1. A device that transforms chemical energy into electrical energy A. secondary battery B. cell C. battery D. primary battery

ANSWER: B 2. A device that is capable of converting chemical energy into electrical energy A. generator B. battery C. converter D. cell

ANSWER: D 3. A secondary cell whose active positive plate consists of nickel hydroxide, and active negative-plate material is powdered iron oxide mixed with cadmium. Its typical output when fully charged is VO = 1.2V A. Leclanche cell B. dry cell C. Edison cell D. lead-acid cell ANSWER: C 4. If a cell can be charged after it is depleted, it is considered as A. a secondary cell B. a storage cell C. an accumulator D. all of the above

ANSWER: D 5. What type of cell that cannot be recharged which cannot restore chemical reaction? A. nickel-cadmium cell B. secondary cell C. primary cell D. lead-acid wet cell

ANSWER: C 6. A cell whose chemical reaction is not reversible A. primary cell B. secondary cell C. rechargeable cell D. solar cell

ANSWER: A 7. A voltage source in a single container made from one or more cells combines in series, parallel, or series-parallel. A. photoelectric B. thermocouple C. battery D. piezo-electric

ANSWER: C 8. A battery means A. cells connected in series B. cells connected in parallel C. cells connected in series-parallel D. all of the above

ANSWER: D 9. A battery is used to A. supply a steady dc voltage B. supply an unstable dc voltage C. supply an ac voltage D. supply an ac/dc voltage

ANSWER: A 10. In a dry cell, what will happen to the internal resistance as it aged? A. decreases B. increases C. remains constant D. decreases or increases, depends on the chemical composition ANSWER: B 11. The maximum current a cell can deliver through a 0.01 ohm load during testing A. flash current B. surge current C. ideal current D. full-load current

ANSWER: A 12. In batteries, the material used to insulate the positive plates from negative plates are technically called A. insulator B. break-point C. coupler D. separator

ANSWER: D 13. How long will a battery need to operate a 240 Watts equipment, whose capacity is 100Ah and 24 volts rating? A. 5 hrs B. 10 hrs C. 1 hr D. 0.10 hr

ANSWER: B 14. A battery is rated 20 A-hr and is delivering a current of 2A. How long does it last? A. 1 hr B. 5 hrs C. 8 hrs D. 10 hrs

ANSWER: D 15. A primary cell with carbon and zinc as its positive and negative electrodes respectively, and an electrolyte of either a gel or paste. This is commonly known as dry cell. A. Leclanche cell B. Edison cell C. storage cell D. solar cell

ANSWER: A 16. Find the output of a four (4) lead acid cells. A. 3.2 V B. 8.4 V C. 5.8 V D. 12 V

ANSWER: B 17. Silver-cadmium cell has a nominal open-circuit voltage of A. 1.05 V B. 1.5 V C. 2.1 V D. 2.2 V

ANSWER: A 18. Output of six carbon-zinc cells connected in series A. 3 V B. 6 V C. 6.6 V D. 9 V

ANSWER: D 19. The flat 9-V battery, has how many cells in series? A. 3 B. 4 C. 6 D. 9

ANSWER: C 20. Output of automotive battery with six lead-acid cells in series A. 6V B. 12V C. 24V D. 48V

ANSWER: B 21. Substance, which generates a voltage when exposed to light. A. generating substance B. photovoltaic material C. thermoelectric generator D. hydroelectric generator

ANSWER: B 22. A cell whose voltage is generated as a function of light A. photovoltaic cell B. thermoelectric cell C. photodiode D. LED

ANSWER: A 23. Substance used in photovoltaic cells A. Silicon B. Selenium C. Germanium D. All of these

ANSWER: D 24. A junction between two conductors that exhibits electrical characteristics under condition of changing temperature

A. pn junction B. photojunction C. thermoelectric junction D. hydroelectric junction

ANSWER: C 25. Electricity that is generated due to heat, as in thermocouple. A. thermodynamics B. thermojunction C. electric heater D. thermoelectricity

ANSWER: D 26. The source of mechanical power to turn the rotors of alternators, large and small, A.C. and D.C. A. prime contactor B. primer C. prime mover D. prime user

ANSWER: C 27. Electrical machines refer to machines that convert ________ A. mechanical to electrical energy B. electrical to mechanical energy C. electrical energy of one form to electrical energy of another form D. all of the above

ANSWER: D 28. Electrical machines that convert mechanical energy to electrical energy. A. generators B. motors C. cycloconverters D. frequency converters

ANSWER: A 29. Electrical machine that converts ac voltage to dc voltage, or vice versa. A. generator B. motor C. rotary converter D. frequency converter

ANSWER: C 30. Electrical machine that changes ac voltage at one frequency to another ac voltage at another frequency. A. generator B. motor C. rotary converter D. frequency converter

ANSWER: D 31. It consist of a single coil rotated in a magnetic field and produces an A.C. voltage. A. field winding B. armature C. commutator D. elementary generator

ANSWER: D 32. Generation of voltage in a generator can only happen when? A. there is a rotary conductor

B. there is a magnetic field in a conductor C. there is a relative motion between conducting wires and magnetic lines of force D. there is a relative motion between a conductor and electric field

ANSWER: C 33. Two essential parts in rotating generators A. electro/permanent magnets and armature winding B. electromagnets or permanent magnets and commutator C. commutator and armature winding D. brushes and commutator

ANSWER: A 34. In electrical machines, what do you call the set of conductors wound on laminated cores of good magnetic permeability? A. armature core B. armature winding C. rotary winding D. rotary core

ANSWER: B 35. In dc generator, what converts the alternating emf to DC? A. armature B. commutator C. diode D. alternator

ANSWER: B 36. Generally, in dc generators A. The armature winding is rotated with respect to a stationary magnetic field produced by electromagnets or permanent magnets. B. The electromagnets or permanent magnets (magnetic fields) are rotated with respect to the stationary armature winding. C. Current is sent into the armature winding; or the armature winding is usually placed in a stationary laminated iron core and the rotating element may or may not be a set of magnet poles, it depends on the type of motor. D. The armature winding is supplied with current; or the armature is placed inside a set of radially supported magnetic poles. ANSWER: A 37. In electrical machines, what type of voltage is generated at the armature winding? A. dc B. pulsating dc C. ac D. ac or dc depending on the type of machine

ANSWER: C 38. Generally in ac generators A. The armature winding is rotated by a stationary magnetic field produced by electromagnets or permanent magnets. B. Current is sent into the armature winding; or the armature winding is usually placed in a stationary laminated iron core and the rotating element may or may not be a set of magnet poles, it depends on the type of motor. C. The electromagnets or permanent magnets (magnetic fields) are rotated with respect to the stationary armature winding. D. The armature winding is supplied with current; or the armature is placed inside a set of radially supported magnetic poles.

ANSWER: C 39. A dc generator whose excitation is produced by a winding connected to its ow

n positive and negative terminals. A. series generator B. separately excited shunt generator C. self-excited shunt generator D. compound generator

ANSWER: C 40. What is true about field poles in electric machines? A. there are always even number of them (exist by pair) B. there are always an odd number of them C. there are an even or an odd number of them D. none of the above

ANSWER: A 41. In a compound generator, which field winding usually, has a lower resistance? A. series field winding B. shunt field winding C. armature winding D. excitation winding

ANSWER: A 42. Which winding in a dc-compound generator that is relatively made of fine wires? A. armature winding B. excitation winding C. shunt field winding D. series field winding

ANSWER: C 43. What important characteristic you should consider in choosing a dc-generator? A. voltage capacity B. current capacity C. voltage vs. load D. power rating

ANSWER: C 44. What is the purpose of laminating the field poles and armature of a dc machine? A. to reduce eddy current B. to avoid contaminants C. to provide isolation D. to beautify the machine

ANSWER: A 45. An alternator with a lagging power factor of 0.8 will have a ________ voltage regulation at unity power factor. A. 0% B. less than C. greater than D. 100%

ANSWER: C 46. With alternators connected in parallel, the frequency of the system can be changed by A. increasing the field excitation B. decreasing the field excitation C. changing the rpm of the prime movers D. synchronizing the prime movers

ANSWER: C 47. With alternators connected in parallel, the voltage of the system can be changed by A. changing the field excitation B. increasing the speed of the prime movers C. changing the rpm of the prime movers D. synchronizing the prime movers

ANSWER: A 48. If an ac generator is to be driven from prime mover having variable speed, such as aircraft engine, a ________ must be used. A. constant speed drive (CSD) B. regulator C. conditioner D. peak limited

ANSWER: A 49. Find the frequency in kilocycles per second in the armature of a 10 pole, 1,200 rpm generator. A. 100 B. 1000 C. 10 D. 0.1

ANSWER: D 50. What should be the speed of a 6-pole ac generator in order to have a frequency of 50Hz? A. 100 rpm B. 500 rpm C. 1000 rpm D. 1500 rpm

ANSWER: C 51. What is the voltage regulation when the full load voltage is the same as no-load voltage assuming a perfect voltage source? A. 100% B. 1% C. 10% D. 0%

ANSWER: D 52. Calculate the voltage regulation of a generator having a no-load voltage of 220 V and a full load voltage of 180 V. A. 18% B. 22% C. 28% D. 32%

ANSWER: B 53. Usually used to drive low-speed alternators A. diesel engines B. jet propulsion engines C. steam turbines D. hydraulic turbines

ANSWER: D 54. Is usually used to drive high-speed alternators A. diesel engines B. pneumatic engines

C. steam turbines D. hydraulic turbines

ANSWER: C 55. Which statement is true regarding alternators? A. high-speed alternators are smaller than low-speed B. low-speed alternators are smaller than high-speed C. high-power alternators are smaller than low-power D. high-voltage alternators are smaller than low-voltage ANSWER: A 56. For what reason, why carbon brushes are widely used dc machines? A. it is abundant B. it is cheap C. it has a high voltage drop D. it lubricates and polishes the contacts

ANSWER: D 57. Alternators have less chance to hunt if driven by A. steam turbines B. hydroturbines C. diesel turbines D. nuclear reactor

ANSWER: A 58. In alternators, what is the purpose of damper windings? A. it prevents over speeding B. it maintain constant speed C. it prevents hunting D. it protects overloading

ANSWER: C 59. What term applies to the use of two or more generators to supply a common load? A. on-line operation B. series operation C. cascaded operation D. parallel operation

ANSWER: D 60. In paralleling ac generators, ________ is very important. A. voltage level B. current level C. phase angle D. internal resistance

ANSWER: C 61. Description used for generators trying to self-adjust its parameters before paralleling with on line generators. A. synchronizing B. sequencing C. jogging D. alighning

ANSWER: C 62. In changing power from one generator to another, what do you call the operational sequence wherein the incoming generator is connected first before removing the existing generator? A. No Break Power Transfer (NBPT) B. UPS C. LIFO

D. Standby Power transfer

ANSWER: A 63. What do you mean by break power transfer? A. The incoming generator will be connected first to the bus bar before disconnecting the existing generator. B. The present on-line generator will be disconnected first before connecting the incoming generator. C. The incoming generator will only be connected to the bus bar when the bus bar breaks. D. The present on-line generator will be disconnected first and then reconnected together with the incoming generator.

ANSWER: B 64. How alternators rated? A. in Watts B. in kW C. in kVar D. in kVA

ANSWER: C 65. In electrical power distribution, what do you call the first distribution line from the main generating station? A. main transmission lines B. primary distribution lines C. sub transmission lines D. secondary distribution lines

ANSWER: A 66. The lines which carry the energy from the transformer to a customer’s services are called ________. A. main transmission lines B. primary distribution lines C. sub transmission lines D. secondary distribution lines

ANSWER: D 67. In electrical power Generating/distribution Company, which do you think is their highest expenses? A. generation of power B. distribution of power to the consumers C. power transmission D. substations

ANSWER: B 68. In electrical power distributions, what insulator is generally used? A. rubber B. wood C. plastic D. porcelain ANSWER: D 69. Electrical machines refer to machines that convert ________ A. mechanical to electrical energy B. electrical to mechanical energy C. electrical energy of one form to electrical energy of another form D. all of the above

ANSWER: D 70. Electrical machines that convert electrical energy to mechanical energy. A. generators

B. motors C. rotary converters D. frequency converters

ANSWER: B 71. Synchronous type of ac-motor, A. uses a dc-generator to supply dc-excitation to the rotating field B. uses pulsating dc C. uses alternator D. has an ac or dc depending on the type of machine

ANSWER: A 72. Generally in dc motors A. the armature winding is rotated by a stationary magnetic field produced by electromagnets or permanent magnets. B. current is sent into the armature winding; or the armature winding is usually placed in a stationary laminated iron core and the rotating element may or may not be a set of magnet poles, it depends on the type of motor. C. the electromagnets or permanent magnets (magnetic fields) are rotated with respect to the stationary armature winding. D. the armature winding is supplied with current; or the armature is placed inside a set of radially supported magnetic poles.

ANSWER: D 73. In ac motors, generally A. current is sent into the armature winding; or the armature winding is usually placed in a stationary laminated iron core and the rotating element may or may not be a set of magnet poles, it depends on the type of motor. B. the armature winding is supplied with current; or the armature is placed inside a set of radially supported magnetic poles. C. the armature winding is rotated by a stationary magnetic field produced by electromagnets or permanent magnets. D. the electromagnets or permanent magnets (magnetic fields) are rotated with respect to the stationary armature winding.

ANSWER: A 74. Among the dc motors, which produces the highest torque? A. series B. shunt C. compound D. differentially compounded

ANSWER: A 75. Dc motor that has the most stable speed. A. differentially compounded B. compound C. shunt D. series

ANSWER: C 76. In dc motors, when does severe arcing happens? A. during starting B. during rated speed C. during speed fluctuation D. during shutdown

ANSWER: A 77. What is the primary reason why carbon brushes are preferred over copper brushes in dc motors? A. they have low loss

B. they are more strong C. they produce less arcing D. all of the above

ANSWER: C 78. In dc motors, the emf developed which opposes to the supplied voltage. A. residual emf B. induced emf C. coercive emf D. counter emf or back emf

ANSWER: D 79. To minimize arcing during starting of dc motors, a resistance should be added to limit the current in the ________ A. series field winding B. shunt field winding C. armature winding D. all of these

ANSWER: C 80. Which dc motors whose speed is greatly affected by a change in load? It will even run-away if the load is removed. A. series B. shunt C. cumulatively compounded D. differentially compounded

ANSWER: A 81. Motors whose speed can be easily controlled. A. dc motors B. ac motors C. ac & dc motors D. ac or dc motors

ANSWER: A 82. When a dc motor has no load, what will happen to the back emf? A. reduces B. increases C. becomes maximum D. becomes zero

ANSWER: C 83. When can we get a maximum mechanical power from a dc motor? A. Eb = 0 B. Eb = ½V C. Eb = 1V D. Eb = 2V

ANSWER: B 84. The torque of a dc motor is A. directly proportional to the field strength B. inversely proportional to the field strength C. directly proportional to the armature current D. A and C are correct

ANSWER: D 85. One causes why the shaft torque is less than the developed armature torque of a dc motor. A. eddy current B. field loss

C. brushes loss D. friction loss

ANSWER: D 86. For heavy-duty dc motor, how does the effect of armature reaction be corrected? A. using interpoles & brush shifting B. using interpoles C. using compensatory winding D. B & C are correct

ANSWER: D 87. Considered as a variable speed motor A. compounded B. differentially compounded C. shunt D. series

ANSWER: D 88. What is the most common method used in varying the speed of a dc motor? A. by varying the supply voltage B. by changing the effective number of conductors in series C. by varying the armature resistance D. by varying the field strength

ANSWER: D 89. The running speed of a dc series motor is greatly affected by what factor? A. field excitation B. load C. armature resistance D. supply voltage

ANSWER: B 90. In choosing a motor for a particular application, what characteristic you should consider? A. speed-torque B. speed-armature current C. speed efficiency D. speed power

ANSWER: A 91. What will happen to the dc shunt motor if the load torque greatly increases? A. the speed will decrease B. there will be a great increase in current C. the speed almost remains constant D. B and C are correct

ANSWER: D 92. What will happen to a dc series motor when its load is removed? A. the motor will stop B. the motor speed remains the same C. the torque remains the same D. the motor will overspeed

ANSWER: D 93. A motor whose speed increases as the load is increased. A. series dc B. dc shunt C. cumulatively compounded

D. differentially compounded

ANSWER: D 94. Factor(s) that affect iron losses in a dc motor. A. flux B. speed C. armature resistance and flux D. A and B are correct

ANSWER: D 95. One advantage of a cumulatively compounded motor is that it does not run widely at light loads, this feature is due to A. shunt winding B. brake winding C. series winding D. clutch winding

ANSWER: A 96. In applications where an almost constant speed is required, a _______ motor is a good choice. A. dc shunt B. dc series C. cumulatively compounded D. differentially compounded

ANSWER: A 97. In applications where a high torque is needed during starting a _______ motor is preferred. A. dc shunt B. dc series C. differentially compounded D. cumulatively compounded

ANSWER: B 98. In applications where sudden heavy loads happen for short duration, a _______ motor is the best choice. A. dc shunt B. dc series C. cumulatively compounded D. differentially compounded

ANSWER: C 99. In motors of the same rating, which has the least starting torque? A. dc shunt B. dc series C. differentially compounded D. cumulatively compounded

ANSWER: A 100. Factor(s) that affect friction and winding loses in dc motors. A. speed B. armature current C. interpoles D. armature resistance

ANSWER: A 101. In dc motors, power loss is contributed greatly by A. flux loss B. core loss C. copper loss

D. mechanical friction

ANSWER: C 102. Dirt on the commutator may produce A. isolation B. excessive sparking C. power loss D. lower torque

ANSWER: B 103. Motor vibrations are usually caused by A. loose coupling B. dirt on the commutator C. much brush tension D. worn bearings

ANSWER: D 104. When a motor is overloaded, it will usually A. slow down B. speed up C. vibrate D. overheat

ANSWER: D 105. Which motor that produces the highest increase in torque considering the same increase in current? A. dc shunt B. dc series C. differentially compounded D. cumulatively compounded

ANSWER: B 106. When an armature opens in dc motor, it may cause A. intermittent sparking B. an increase in speed C. the motor to slow down D. the motor to stop rotating

ANSWER: A 107. Why do motors take large current during starting? A. the armature resistance is still low B. the field produced is still weak C. it has to break the momentum D. there’s still a low back emf

ANSWER: D 108. In dc motors, the speed will A. increase with an increase in field strength B. decrease with an increase in field strength C. decrease as the supply voltage is increased D. B and C are correct

ANSWER: B 109. When armature current is increased in a dc motor, its armature reaction will A. also increase B. decrease C. increase exponentially D. decrease exponentially

ANSWER: A 110. Why does in dc motor, brushes are positioned such that they will be with the direction of the rotation? A. to reduce sparking B. to last long C. to have less loss D. all of the above

ANSWER: A 111. Motors are used to convert electrical energy to mechanical energy. What type of motor that is best suited for heavy-load application? A. dc series motors B. dc compound motors C. single phase motors D. polyphase motors

ANSWER: D 112. DC shunt motor speed can be controlled electronically by using a _______ in series with the armature winding. A. thyrector B. potentiometer C. rheostat D. thyristor

ANSWER: D 113. Which thyristor is commonly used is motor speed control? A. triac B. diac C. SCR D. SUS

ANSWER: C 114. In controlling motor speed, the SCRs controls the A. number of pulses B. phase angle C. firing angle D. any of these

ANSWER: C 115. How do you reverse the rotation of a dc shunt motor? A. By reversing the direction of the field current, leaving the armature current the same. B. By reversing the direction of the armature current, leaving the field current the same. C. By reversing both field and armature current D. Either A or B

ANSWER: D 116. In motor speed control, what is responsible for SCR firing? A. trigger circuit B. threshold circuit C. reference circuit D. holding circuit

ANSWER: A 117. A circuit that converts ac-voltage to dc-voltage A. rectifier B. inverter C. dc-converter D. ac-converter

ANSWER: A 118. Conversion from dc-voltage to another dc-voltage requires a A. inverter B. cycloconverter C. dc-converter D. ac-converter

ANSWER: C 119. A converter that changes ac-voltage to another ac-voltage level. A. inverter B. cycloconverter C. dc-converter D. ac-converter

ANSWER: D 120. What converter must be used if one wished to change dc-voltage into ac-voltage? A. inverter B. cycloconverter C. dc-converter D. ac-converter

ANSWER: A 121. A converter that changes ac-voltage frequency from one to another. A. inverter B. cycloconverter C. dc-converter D. ac-converter

ANSWER: B 122. In electronic converters, what signal is mostly used to trigger the active device? A. sine-wave B. square-wave C. triangular-wave D. sawtooth-wave

ANSWER: B 123. A transformer consist of the following: A. An inductance and resistance B. A parallel resonant circuit C. A capacitor and an inductor D. Two coils wound on a common core

ANSWER: D 124. Transformer is considered by many as an efficient device due to the fact that A. it uses an inductive coupling B. it is magnetically coupled C. it is a static device D. it is electrically coupled

ANSWER: C 125. With transformer, what is measured when performing open-circuit test? A. turns ratio B. copper loss C. leakage reactance D. turns impedance

ANSWER: B 126. Open-circuit test with transformers is always done on what winding? A. low-voltage B. high-voltage C. primary D. secondary

ANSWER: A 127. Short-circuit test with transformers is always done on what winding? A. low-voltage B. high-voltage C. primary D. secondary

ANSWER: A 128. When the transformer secondary winding is short-circuited, its primary inductance will A. become zero B. decrease C. increase D. not be affected

ANSWER: C 129. Cooling system for transformers with ratings less than 5kVA A. forced-air cooling B. oil-cooling C. natural air cooling D. water cooling

ANSWER: C 130. For transformers, zero efficiency happens when it has A. no-load B. 1/2 of full-load C. 2/3 of full-load D. full-load

ANSWER: A 131. For transformers, maximum efficiency happens when A. copper loss is zero B. copper loss is equal to constant loss C. the primary and secondary windings are equal D. the leakage reactances of both windings are equal

ANSWER: B 132. In constructing transformers, the primary and secondary windings should have A. good electrical coupling B. loose magnetic coupling C. tight magnetic coupling D. best inductive coupling

ANSWER: C 133. What are the two parameters in transformers that are the same in both primary and secondary? A. power and voltage B. power and current C. power and impedance D. voltage per turn and ampere-turns

ANSWER: D

134. In transformers, the amount of copper used in the primary is A. less than that of the secondary B. greater than that of secondary C. exactly twice that of secondary D. almost equal as that of secondary

ANSWER: D 135. At very low frequencies, transformers woks poorly because A. its magnetizing current will be very high B. its core permeability will be greatly increased C. its core permeability will be greatly reduced D. its impedance will increase

ANSWER: A 136. What will happen if a power transformer is to be operated at a very high frequency? A. it will have a very high core loss B. its impedance will decrease C. its core permeability will be greatly increased D. its core permeability will be greatly reduced

ANSWER: A 137. How are the primary and secondary coupled in autotransformers? A. electrically B. magnetically C. electrically and magnetically D. capacitively

ANSWER: C 138. In a single-phase transformer, the core flux is A. constant B. pulsating C. alternating D. alternating and sometimes stable

ANSWER: C 139. What do you think will happen to a transformer when its primary is connected to a DC supply? A. It will become more efficient B. It will become less efficient C. It will have good regulation D. It might burn out

ANSWER: D 140. Generally, in what application you consider the use of core-type transformers? A. low voltage and low current B. low voltage and high current C. high voltage and low current D. high voltage and high current

ANSWER: C 141. In ________ transformers, when its primary is energized the secondary should never be open-circuited. A. power B. voltage C. current D. matching

ANSWER: C

142. Considered as an ideal transformer A. the one with no losses and leakage reactance B. the one with 100% regulation C. the one with zero efficiency D. the one with equal primary and secondary

ANSWER: A 143. What is the effect of air gaps at the transformer core? A. Its reluctance is decreased B. It increases eddy current C. It decreases hysteresis loss D. It increases magnetizing current

ANSWER: D 144. ________ currents are wasteful currents which flows in cores of transformers and produces heat. A. Residual B. Eddy C. Sneak D. Magnetizing

ANSWER: B 145. What will happen to the eddy current loss in transformers when the load is increased? A. will also increase B. will decrease C. will become infinite D. nothing will happen

ANSWER: D 146. Leakage flux in transformers will cause A. copper loss to increase B. copper loss to decrease C. eddy current to decrease D. voltage drop in the windings

ANSWER: D 147. The increase in temperature in a transformer is mainly due to A. true power B. reactive power C. apparent power D. virtual power

ANSWER: C 148. In transformers, the voltage per turn at the primary is ________ the secondary. A. less than that of B. greater than that of C. a factor of D. the same as

ANSWER: D 149. In transformer windings, the more number of turns A. the higher is the voltage B. the lower is the voltage C. the lower is the impedance D. the higher is the current

ANSWER: A 150. What is true about core-type transformers?

A. It has a shorter magnetic path B. It has a longer magnetic path C. It has a very long magnetic path D. It has an infinite magnetic path

ANSWER: A 151. Practically how many percent is copper loss to the total loss in transformers? A. 15% B. 50% C. 85% D. 100%

ANSWER: C

152. What is the purpose of laminating the core of a transformer? A. to decrease eddy current loss B. to increase eddy current loss C. to decrease copper loss D. to decrease hysteresis loss

ANSWER: A 153. Large transformers have approximately an efficiency of A. 25% B. 45% C. 75% D. 95%

ANSWER: D 154. The loss in a transformer due to the changing field is called A. leakage B. hysteresis loss C. eddy loss D. keeper

ANSWER: B 155. The ratio of the amount of magnetic flux linking a secondary coil compared to the flux generated by the primary coil: A. coupling factor B. mutual coupling C. coefficient of coupling D. hysteresis factor

ANSWER: C 156. Mutual inductance between two coils can be decreased by A. moving the coils apart B. inserting an iron core C. moving the coils close D. reducing the reluctance ANSWER: A 157. An advantage of full-wave rectifier over half-wave rectifier. A. Each diode can cool-off during half of each input cycle B. The ripple frequency is lower C. The tube will conduct during both halves of the input cycle D. Output voltage is lower with more ripple

ANSWER: C 158. One of the following items below is not one of the main components of an alternating current power supply. A. Power transformer

B. Voltage regulator C. Rectifier D. Filter

ANSWER: C 159. Most electronic devices/circuits require dc-voltage to operate. A battery is a good power source, however, its operating time is limited. The use of battery also proves to be expensive. A more practical alternative is to use the household main supply, and since this is an ac-voltage, it must be converted to a dc-voltage. The circuit that converts this ac-voltage to a dc-voltage is called A. rectifier B. clamper C. filter D. regulator

ANSWER: A 160. A rectifier that uses either the positive or negative portion only of the main ac-supply A. half-wave B. full-wave C. full-wave bridge D. all of the above

ANSWER: A 161. For a half-wave rectifier, the average output voltage is _______ of the maximum ac-voltage. A. 31.8% B. 45% C. 63.6% D. 90%

ANSWER: A 162. Percent ripple of a half-wave rectifier. A. 24% B. 48% C. 63.6% D. 121%

ANSWER: D 163. Calculate the dc-voltage at the output of a half-wave rectifier with a 12Vrms input. A. 2.7 V B. 3.8 V C. 4.5 V D. 5.4 V

ANSWER: D 164. To double the capability of the half-wave rectifier, a _______ must be used. A. full-wave rectifier B. full-wave bridge C. dual-supply D. A or B is correct

ANSWER: D 165. Fullwave rectifier defers from fullwave bridge in what aspect? A. fullwave uses two diodes, while four for fullwave bridge B. diode’s PIV in fullwave is twice that of fullwave bridge C. fullwave generates less heat than fullwave bridge D. all of the above

ANSWER: D 166. Common to both full-wave and full-wave bridge rectifiers A. dc-voltage B. ripple factor C. ripple frequency and percent ripple D. all are correct

ANSWER: D 167. Find direct current voltage from a full-wave rectifier with 120 V peak rectified voltage. A. 60 V B. 7.639 V C. 76.39 V D. 6.0 V

ANSWER: C 168. The dc-voltage of a full-wave bridge rectifier. A. 0.318 Vmax B. 0.45 Vmax C. 0.636 Vmax D. 0.90 Vmax

ANSWER: C 169. Relate the magnitude of the dc-output voltage to the ac input rms voltage of a full-wave rectifier. A. VDC = 0.318 Vrms B. VDC = 0.45 Vrms C. VDC = 0.636 Vrms D. VDC = 0.90 Vrms

ANSWER: D 170. Determine the dc-voltage of a full-wave bridge rectifier when the input ac-voltage is 24 Vrms. A. 7.63 V B. 10.8 V C. 15.3 V D. 21.6 V

ANSWER: D 171. Ripple factor of a full-wave rectifier. A. 0.318 B. 0.48 C. 0.9 D. 1.21

ANSWER: B 172. To improve the dc output voltage of a power supply, a _______ A. shunt resistor may be installed B. limiting resistor may be installed C. feedback element may be installed D. filter capacitor may be installed

ANSWER: D 173. Factor(s) that can reduce the ripple voltage of a power supply. A. filter capacitance B. reduction of load current C. increase in input frequency D. all of the above

ANSWER: D 174. Making the filter capacitor large in a power supply results to A. an increase of the ripple voltage B. an increase of the dc-voltage C. a decrease of the ripple frequency D. A and B above

ANSWER: B 175. Find the ripple factor (kr) of a sinusoidal signal with peak ripple of 4 volts on an average of 30. A. 0.094 B. 0.013 C. 0.130 D. 0.94

ANSWER: A 176. Calculate the peak-to-peak ripple voltage of a 20 V full-wave power supply with a filter capacitor C = 220 μF when delivering a load current of 50 mA. A. 2.0 Vpp B. 3.79 Vpp C. 5.67 Vpp D. 7.9 Vpp

ANSWER: A 177. In capacitor-filtered power supply, what will happen to the ripple voltage if the load is disconnected? A. increases B. becomes infinite C. becomes unpredictable D. drops to zero

ANSWER: D 178. For a power supply with a peak-to-peak ripple voltage of 5 Vpp, determine its rms ripple. A. 1.44 Vrms B. 1.77 Vrms C. 2.88 Vrms D. 3.54 Vrms

ANSWER: B 179. A 20-Vdc power supply was found to have a ripple voltage of 2 Vrms when supplying 1.5 amps load. Calculate its percent ripple. A. 7.5 % B. 10.0 % C. 12.5 % D. 15.0 %

ANSWER: B 180. Which power supply filter gives the smallest ripple voltage? A. capacitor filter B. RC-filter C. LC-filter D. multi-section LC-filter

ANSWER: D 181. Ripple voltage in power supplies causes unwanted effects on the load it is supplying, i.e. a hum in audio amplifiers. To minimize this effect several filtering techniques are used, however, ripple still exists. What is a better alternative to reduce further the ripples? A. truncation

B. clipping C. clamping D. regulation

ANSWER: D 182. A voltage regulator connected in parallel with the load. A. series regulator B. parallel regulator C. shunt regulator D. switching regulator

ANSWER: C 183. Which regulator is the most efficient? A. series B. shunt C. switching D. modulating

ANSWER: B 184. Voltage reference element in most voltage regulators A. diac B. thyrector C. zener diode D. transistor

ANSWER: C 185. In voltage regulators, what do you call the element/device that controls the amount of current/voltage/power? A. sampling circuit B. comparator C. limiter D. control element

ANSWER: D 186. The element/device used as a comparator in most voltage regulators. A. zener diode B. BJT C. IGBT D. op-amp

ANSWER: D 187. Sampling circuit used in most voltage regulators. A. voltage divider network B. bleeder network C. crowbar D. bootstrap circuit

ANSWER: A 188. Most voltage regulators used _______ as their control element. A. BJT B. SBS C. UJT D. JFET

ANSWER: A 189. The most efficient voltage regulator and is therefore used in high-current high-voltage applications. A. series regulators B. shunt regulators C. hybrid regulators

D. switching regulators

ANSWER: D 190. A 12 VDC power supply is regulated using 7805 IC and is used in TTL circuits that require a 0.2 amps current. Determine the dropout voltage of the system. A. 4 V B. 5 V C. 6 V D. 7 V

ANSWER: D 191. A load draws 1 A current from a 10-V regulated power supply. Calculate the power dissipated by the regulator if it has an input voltage of 16 V. A. 6 Watts B. 10 Watts C. 12 Watts D. 16 Watts

ANSWER: A 192. Three-terminal fixed positive voltage regulators commonly used in industry. A. 78XX series B. 79XX series C. 723 IC regulator D. 317 regulator

ANSWER: A 193. What is the regulated output voltage of a 7924 regulator? A. + 4 V B. - 4 V C. + 24 V D. - 24 V

ANSWER: D 194. A three-terminal variable positive voltage regulator A. 317 B. 337 C. 723 D. 741

ANSWER: A 195. What three-terminal IC regulator that has a variable negative voltage output? A. 317 B. 337 C. 723 D. 741

ANSWER: B 196. In a three-terminal adjustable positive voltage regulator (317), what is the band-gap voltage between the output terminal and adjustment terminal? A. 1.25 V B. 2.5 V C. 3.25 V D. 4.125 V

ANSWER: A 197. Typical ripple rejection of most three-terminal voltage regulators A. 0.1 % B. 0.8 %

C. 1.2 % D. 2.0 %

ANSWER: A 198. The three-terminal voltage regulators, such as the 78XX series has a typical current rating of 1.5 amperes. If a high current is required, say 30 amperes, how will you make modifications from this regulator in order to provide the required current? A. by cascading them B. by the use of a crowbar circuit C. by connecting them in parallel D. by the use of external pass transistor

ANSWER: D 199. What is the simplest way of protecting power supplies from reverse-polarity/reverse-current flow? A. by a forward-biased diode B. by a reverse-biased diode C. by a crowbar circuit D. by a snubber circuit

ANSWER: B 200. A crowbar circuit is used A. to monitor the output current of a power supply and automatically shuts down the system when an overload occur. B. to monitor the temperature of a power supply and switches the cooling fan when a threshold temperature is reached. C. as voltage reference in regulated power supplies. D. as an over-voltage protection in power supplies.

ANSWER: D 201. Technique(s) in using low-power, low-voltage transistors in high voltage regulators. A. ground return regulation B. by lifting the regulator above ground C. connecting them in series D. all of the above

ANSWER: D 202. Which of the regulators dissipates less power and therefore generates less heat? A. series B. shunt C. switching D. UPS

ANSWER: C 203. In switching regulators, what are the semiconductor devices that can be used as controllable power switches? A. BJTs and MDs B. MOSFETs and IGBT C. GTOs and thyristors D. all of the above

ANSWER: D 204. In voltage regulators, the control element plays a major part in providing proper and efficient regulation. What are the desirable characteristics of the control element to be used if excellent regulator is desired? A. very small off-state leakage current and high on-state current ratings B. large forward and reverse blocking voltage and very small on-sate voltage

C. short turn-on and turn-off times so that it can be used in high-speed switching regulators D. all of the above

ANSWER: D 205. Active devices used in switching regulators may experience large over-currents during conduction (turn-on-state) and large over-voltages during turn-off. These excessive currents and voltages may cause distraction or damage of the active devices. How do we protect them? A. by the use of a crowbar circuit B. by providing a buck-boost circuit C. by shunting a thyrector D. by installing a snubber circuit

ANSWER: D 206. One of the major concerns in power electronics is to clean-up or shape-up the utility-supply voltage (the wall-outlet 220 V/60 Hz) from disturbances such as, overvolt, undervolt, voltage spikes, and harmonic distortions. What circuit is used for this? A. power conditioners B. UPS C. power inverters D. line scanning

ANSWER: A 207. A power supply that continuously provides protection against undervoltage, overvoltage and even power outages. A. standby power supply B. uninterruptible power supply C. power conditioners D. regulated power supply

ANSWER: B

Test 6 – Test and Measurement

1. What is the degree of exactness of measurement when compared to the expected value of the variable being measured? A. Accuracy B. Error C. Deviation D. Precision

ANSWER: A 2. The art or process of determining the existence or knowing the magnitude of something, directly or indirectly in terms of a recognized standard. A. Measurement B. Testing C. Recording D. Evaluating

ANSWER: A 3. A procedure or sequence of operations for determining whether a component or equipment is functioning or working normally. A. Measurement B. Test C. Recording D. Evaluating

ANSWER: B

4. In measurement, what do you call the degree of exactness compared to the expected value of the variable being measured? A. precision B. accuracy C. sharpness D. correctness

ANSWER: B 5. A measure of consistency or repeatability of measurements is called A. precision B. accuracy C. sharpness D. correctness ANSWER: A 6. Precision is also known as A. correctness B. accuracy C. sharpness D. reproducibility

ANSWER: D 7. In measurements, the sum of a set of numbers divided by the total number of pieces of data in the given set is called A. geometric mean B. algebraic mean C. arithmetic mean D. effective value

ANSWER: C 8. The deviation of a reading from the expected value A. accuracy B. precision C. error D. difference

ANSWER: C 9. Errors due to frictions of the meter movement, incorrect spring tension, improper calibration or faulty instruments: A. Observational errors B. Environmental errors C. Instrument errors D. Gross errors

ANSWER: C 10. When an instrument is subjected to harsh environments such as high temperature, strong magnetic, electrostatic or electromagnetic field, it may have detrimental effects and cause errors known as A. Observational errors B. Environmental errors C. Instrument errors D. Gross errors

ANSWER: B 11. Errors introduced by the observer or user. A. Observational errors B. Environmental errors C. Instrument errors D. Gross errors

ANSWER: A

12. Errors in analog meter reading due to your physical position with respect to the meter scale. A. parallax error B. angular error C. linear error D. deviation ANSWER: A 13. What do you call the difference between any number within the set of numbers and the arithmetic mean of that set of numbers? A. parallax error B. angular error C. linear error D. deviation

ANSWER: D 14. An instrument or device having recognized permanent or stable value that is used as a reference. A. standard instrument/device B. reference instrument/device C. fixed instrument/device D. ideal instrument/device

ANSWER: A 15. The smallest change in a measured variable to which an instrument will respond. A. quantize value B. resolution C. minimum D. step size

ANSWER: B 16. A device or mechanism used to determine the value of a quantity under observation. A. measuring kit B. evaluator C. instrument D. sensor

ANSWER: C 17. What is the basic unit for measuring current flow? A. coulomb B. ampere C. atomic weight D. volt

ANSWER: B 18. An instrument used to detect and measure the presence of electrical current is generally called A. D’Arsonval meter B. electrodynamometer C. galvanometer D. potentiometer

ANSWER: C 19. What is the common type of meter movement? A. Fixed coil B. Farad C. D’Arsonval D. Digital ANSWER: C

20. A permanent-magnet moving-coil instrument. A. induction instrument B. D’Arsonval meter movement C. moving-iron instrument D. moving-magnet instrument

ANSWER: B 21. An instrument which depends on current in one or more foxed-coils acting on one or more pieces of soft iron, at least one of which is movable. A. moving-magnet instrument B. moving-iron instrument C. D’Arsonval meter movement D. induction instrument

ANSWER: B 22. What is that device, which depends on the action of a movable permanent magnet, in aligning itself in the resultant field, produced either by a fixed permanent magnet and adjacent coil or coils carrying current, or by two or more current-carrying coils whose axes are displaced by a fixed angle? A. D’Arsonval meter movement B. induction instrument C. moving-magnet instrument D. moving-iron instrument

ANSWER: C 23. What ammeter is mostly used in measuring high-frequency currents? A. electrostatic B. moving-coil C. dynamometer D. thermocouple

ANSWER: D 24. Measurement of high dc-voltages is usually done by using A. Electrostatic B. moving-coil C. dynamometer D. thermocouple

ANSWER: A 25. Measuring instrument that can be used only to measure voltages. A. electrostatic B. thermocouple C. dynamometer D. permanent-magnet moving-coil

ANSWER: A 26. This instrument measures temperatures by electric means, especially temperatures beyond the range of mercury thermometers. A. pyrometer B. electrostatic instrument C. moving-magnet instrument D. permanent-magnet moving-coil instrument

ANSWER: A 27. This instrument refers to that one, which measures the intensity of the radiation, received from any portion of the sky. A. megaohmmeter B. pyranometer C. Megger D. galvanometer

ANSWER: B 28. What is the normal indication on a megger (megohmmeter) when checking insulation? A. one B. infinity C. middle of scale D. zero

ANSWER: B 29. Resistance measuring instrument particularly used in determining the insulation resistance. A. megaohmmeter B. Megger C. galvanometer D. A or B are correct

ANSWER: D 30. An electrodynamic meter used to measure power A. hook-on type voltmeter B. wattmeter C. watt-hour meter D. multi-meter

ANSWER: B 31. A device used to mechanically measure the output power of a motor. A. dynamometer B. Megger C. concentric-vane instrument D. radial-vane instrument

ANSWER: A 32. An indicating instrument whose movable coils rotate between two stationary coils, usually used as wattmeter. A. induction-type meter B. radial-vane instrument C. electrodynamometer D. concentric-vane instrument

ANSWER: C 33. Dynamometers are mostly used as A. voltmeter B. ammeter C. ohmmeter D. wattmeter

ANSWER: D 34. What damping method is generally used in dynamometers? A. spring B. fluid friction C. eddy-current damping D. air friction

ANSWER: D 35. Which dynamometer instrument has a uniform scale? A. voltmeter B. ammeter C. ohmmeter D. wattmeter

ANSWER: D 36. For a dynamometer to be able to measure high current, a ________ should be used. A. shunt resistor B. multiplier C. CVDT D. current transformer

ANSWER: D 37. Error in voltmeter reading is due to A. insertion B. loading C. battery aging D. conversion

ANSWER: B 38. Error in ammeter reading id due to A. insertion B. loading C. battery aging D. conversion

ANSWER: A 39. Which type of meter requires its own power source? A. A voltmeter B. An ammeter C. An ohmmeter D. A wattmeter

ANSWER: C 40. Error in ohmmeter reading is due to A. insertion B. loading C. battery aging D. meter friction

ANSWER: C 41. Decreasing the value of the shunt resistor of an ammeter, its current measuring capability A. increases B. decreases C. remains constant D. none of the above

ANSWER: A 42. Increasing the value of the series resistor of a voltmeter, its voltage measuring capability A. increases B. decreases C. remains constant D. none of the above

ANSWER: A 43. A device that is used to measure current without opening the circuit A. megger test B. clamp probe C. ammeter D. multi-meter

ANSWER: B

44. Which of the ammeter below that has no insertion error? A. D’Arsonval meter B. clamp-meter C. micrometer D. meter with current transformer

ANSWER: B 45. To prevent damage of the multirange ammeter during selection, a/an _______ should be used. A. direct shunt B. selected shunt C. Ayrton shunt D. shunt fuse

ANSWER: C 46. For the greatest accuracy, what should be the input impedance of a VOM be? A. 1,000 ohms/V B. 50,000 ohms/V C. as large as possible D. as small as possible

ANSWER: C 47. Voltage measurement in a high impedance circuit requires a voltmeter with A. low input impedance B. high input impedance C. high voltage probe D. low voltage probe

ANSWER: B 48. A meter has a full-scale current of 50μA, what is its sensitivity? A. 20kΩ/V B. 20V/Ω C. 50kΩ/V D. 50μA/V

ANSWER: A 49. If a meter with a full-scale current of 100μA is used as an ac voltmeter with half-wave rectification, its ac sensitivity is A. 10,000 Ω/V B. 4,500 Ω/V C. 9,000 Ω/V D. 100 Ω/V

ANSWER: B 50. In order to make an accurate measurement as possible, the internal resistance of a voltmeter must be A. as high as possible B. as low as possible C. proportional to the voltage range D. proportional to the current range

ANSWER: A 51. An ammeter has a full-scale deflection current of 100mA. If the same ammeter is used to measure a full-scale current of 1.0 ampere, what is the value of the shunt resistor in ohms if the voltage across the meter is 9.0 volts? A. 9.0 B. 10 C. 900 D. 100

ANSWER: B 52. What is the purpose of the rheostat in ohmmeter? A. balancing resistance B. counter resistance of measured circuit C. coil resistance D. compensate aging battery of the meter

ANSWER: D 53. The zero-adjust control in an analog type ohmmeter is used to A. compensate for the differing internal battery voltage B. make sure the pointer is moving correctly C. align the infinity resistance position D. align the zero-voltage position ANSWER: A 54. The scale of a hot wire instrument is a/an __________ function. A. linear B. squared C. log D. exponential

ANSWER: B 55. Moving iron instrument have a scale function that is A. log B. exponential C. linear D. squared

ANSWER: D 56. To increase the measuring capability of a moving-iron ac ammeter, a _______ should be used. A. shunt B. multiplier C. swamping resistors D. different number of turns of operating coil

ANSWER: D 57. Which electrical instruments below is the most sensitive? A. moving-iron B. dynamometer C. thermocouple D. PMMC

ANSWER: D 58. Basically, a PMMC instrument can be used only in A. ac measurements B. dc measurements C. rms measurements D. all of the above

ANSWER: B 59. Controlling torque in PMMC. A. spring action B. magnetic action C. electromagnetic action D. tension cable

ANSWER: A 60. What damping method is used in induction type ammeters? A. air friction B. electrostatic damping

C. fluid friction D. eddy current damping

ANSWER: D 61. Induction type instruments are mostly used as A. voltmeter B. ammeter C. wattmeter D. watt-hour meter

ANSWER: D 62. In indicating instruments, what will happen to the controlling torque if the deflection becomes greater? A. increases B. decreases C. remains unchanged D. drops to zero

ANSWER: A 63. The force(s) that is(are) acting on the pointer of an indicating instrument as it rest on its final deflected position. (Note: damping torque is 0). A. controlling torque B. deflecting torque C. damping torque D. A & B above

ANSWER: D 64. What is(are) the force(s) acting on the pointer of an indicating instrument when it is in motion? A. controlling and deflecting torques B. damping and deflecting torques C. controlling and damping torques D. controlling, damping, deflecting torques

ASNWER: D 65. Material that is mostly used as a pointer in indicating instruments. A. soft iron B. aluminum C. silver D. stainless

ANSWER: B 66. A Kelvin electrostatic voltmeter uses what method of damping? A. fluid friction B. spring action C. mechanical friction D. eddy-current damping

ANSWER: A 67. Shunts in meters should have a _________ temperature coefficient of resistance. A. positive B. negative C. very small D. very large ANSWER: C 68. In a moving coil ammeter, a _________ is connected in series with the soil to compensate for temperature variations. A. limiting resistor B. shunt resistor

C. multiplier D. swamping resistor

ANSWER: D 69. Where can we use the dynamometer? A. dc only B. ac only C. dc and ac D. peak measurement

ANSWER: C 70. What is the meter that depends for its operation on the forces of attraction and repulsion between electrically charged bodies? A. induction instrument B. electrostatic instrument C. moving-magnet instrument D. D’Arsonval meter movement

ANSWER: B 71. What do you call of an instrument that depends for its operation on the reaction between magnetic flux set up by currents in fixed windings and other currents set up by electromagnetic induction in movable conducting parts? A. induction instrument B. electrostatic instrument C. moving-magnet instrument D. D’Arsonval meter movement

ANSWER: A 72. A meter for its operation, it depends on a movable iron vane which aligns itself in the resultant field of a permanent magnet and an adjacent current carrying coil. A. induction instrument B. electrostatic instrument C. moving-magnet instrument D. permanent-magnet moving coil-instrument

ANSWER: D 73. What is the measuring instrument that uses the force of repulsion between fixed and movable magnetized iron vanes, or the force between a coil and a pivoted vane-shaped piece of soft iron to move the indicating pointer? A. pyrometer B. vane-type instrument C. electrostatic instrument D. moving-magnet instrument ANSWER: B 74. It’s an electrostatic voltmeter in which an assembly of figure – 8 – shaped metal plates rotates between the plates of a stationary assembly when a voltage is applied between the assemblies. The length of the arc of rotation is proportional to the electrostatic attraction and thus, to the applied voltage. A. varmeter B. variometer C. potentiometer D. Kelvin voltmeter

ANSWER: D 75. What is that instrument used for measuring the strength and direction of magnetic fields? A. varmeter B. potentiometer C. magnetometer

D. Kelvin voltmeter

ANSWER: C 76. What do you call of that instrument used for measuring reactive power in vars? A. varmeter B. pyrometer C. reactive volt-ampere meter D. A or C is correct

ANSWER: D 77. What is this instrument or circuit that has four or more arms, by means of which one or more of the electrical constants of an unknown component may be measured? A. bridge B. Hazeltine circuit C. Loftin – White circuit D. D’Arsonval meter movement

ANSWER: A 78. A four-arm bridge. Al arms of which are predominantly resistive; used for measuring resistance. A. bridge B. resistance bridge C. Wheatstone bridge D. B or C is correct

ANSWER: D 79. This is the method of using a Wheatstone bridge to determine the distance from the test point to a fault in a telephone or telegraph line or cable. A. Mesh B. Varley loop C. Batten system D. Cordonnier system ANSWER: B 80. This refers to a four-arm ac bridge used for measuring inductance against a standard capacitance. A. Maxwell bridge B. slide-wire bridge C. resistance bridge D. Wheatstone bridge

ANSWER: A 81. Refers to an ac bridge for measuring the inductance and Q of an inductor in terms of resistance, frequency and a standard capacitance. A. Hay bridge B. Maxwell bridge C. slide-wire bridge D. Wheatstone bridge

ANSWER: A 82. This is a special bridge for measuring very low resistance (0.1Ω or less). The arrangement of the bridge reduces the effects of contact resistance, which causes significant error when such low resistances are connected to conventional resistances bridges. A. Hay bridge B. Maxwell bridge C. Wheatstone bridge D. Kelvin double bridge

ANSWER: D 83. A type of four-arm capacitance bridge in which the unknown capacitance is compared with a standard capacitance. This bridge is frequently employed in testing electrolytic capacitors, to which a dc polarizing voltage is applied during the measurement. What is this bridge? A. Hay bridge B. Maxwell bridge C. Schering bridge D. Wheatstone bridge

ANSWER: C 84. What do you call of that frequency-sensitive bridge in which two adjacent arms are resistances and the other two arms are RC combinations? A. Hay bridge B. Wein bridge C. Maxwell bridge D. Schering bridge

ANSWER: B 85. When the capacitors of a Wein bridge are replaced by inductors, the bridge becomes A. Wein-bridge filter B. variometer C. Schering bridge D. Wein inductance bridge

ANSWER: D 86. A simplified version of the Wheatstone bridge wherein, two of the ratio arms are replaced by a 100 cm long Manganin of uniform cross-sections and provided with a slider. A. Hay bridge B. Schering bridge C. slide-wire bridge D. Wein inductance bridge

ANSWER: C 87. Bridge used to measure both inductive and capacitive impedances at higher frequencies. A. Hay bridge B. Schering bridge C. Wein bridge D. radio-frequency bridge

ANSWER: D 88. A bridge wherein all legs are electrically identical A. balance bridge B. balance circuit C. balance line D. all of the above

ANSWER: A 89. Comparison between dc and ac measuring instruments A. generally, ac instruments are less sensitive than dc instruments B. errors such as induced emfs, frequency variations, and harmonic-current components are only present in ac instruments C. in ac instruments, higher value of current is needed than in dc instruments to produce the same deflection D. all of these are correct

ANSWER: D

90. What is an electronic instrument capable of showing on screen and maybe on print, relative spacing of transmitter carriers, their sidebands and harmonics? A. Counters B. Spectrum analyzer C. Triggered oscilloscope D. Multimeter

ANSWER: B 91. An instrument capable of displaying simultaneously the amplitude of signals having different frequencies. A. oscilloscope B. spectrum analyzer C. VTVM D. Logic analyzer

ANSWER: B 92. Spectrum analyzer is A. a real-time analyzer B. a non-real time analyzer C. the same as a wave analyzer in all aspects D. an instrument not dependent on frequency

ANSWER: A 93. Indications of spectrum analyzer is presented by means of A. a moving meter B. an iron vane C. a CRT D. a LED

ANSWER: C 94. An electronic measuring device that provide instantaneous visual indication of voltage excursions. A. voltmeter B. power meter C. oscilloscope D. power line meter

ANSWER: C 95. An instrument that is capable of displaying waveforms by means of fluorescence in a CRT. A. oscilloscope B. wave analyzer C. spectrum analyzer D. distortion analyzer

ANSWER: A 96. Types of oscilloscopes that are able retain the display for a longer period for analysis. The display is retained by the use of flood gun. A. sampling oscilloscope B. digital storage oscilloscope C. storage oscilloscope D. delayed sweep oscilloscope

ANSWER: C 97. What do call an oscilloscope that uses sampling technique in processing signals having frequencies beyond its normal capabilities? A. sampling oscilloscope B. digital storage oscilloscope C. storage oscilloscope D. delayed sweep oscilloscope

ANSWER: A 98. Generally, oscilloscope uses what type of deflection? A. magnetic deflection B. electromagnetic deflection C. static deflection D. electrostatic deflection

ANSWER: D 99. A device or instrument, which delivers signals of pre3cise frequency and amplitude, usually over a wide range. A. synthesizer B. frequency generators C. signal generators D. modulators

ANSWER: C 100. The two most common audio oscillators are A. Wein bridge and Colpitts B. Wein bridge and phase-shift C. Colpitts and Hartley D. Hartley and phase-shift

ANSWER: B 101. What are the two most popular RF oscillators A. Wein bridge and Colpitts B. Wein bridge and phase-shift C. Colpitts and Hartley D. Hartley and phase-shift

ANSWER: C 102. A device or instrument able to generate noise with accurate voltage for test purposes. A. signal generator B. synthesizer C. frequency generator D. noise generator

ANSWER: D 103. When do you need a noise generator? A. When starting an oscillators B. When evaluating noise performance of an oscillator C. When evaluating noise characteristics of an amplifier D. When performing modulation analysis

ANSWER: C 104. In RF or microwave system, what instrument is used to measure the incidental and reflected signals. A. oscilloscope B. reflectometer C. incident-wave meter D. spectrum analyzer

ANSWER: B 105. A type of photometer used to measure reflection. A. photodiode B. reflectometer C. incident-wave meter D. LED

ANSWER: B 106. A tunable RF instrument, which, by means of a sharp dip of an indicating meter, indicates resonance with an external circuit under test. A. reflectometer B. inclinometer C. dip meter D. Grid-dip meter

ANSWER: C 107. A type of dip meter employing a vacuum tube oscillator, whose indicating dc microammeter is in the grid circuit. A. reflectometer B. inclinometer C. dip meter D. Grid-dip meter

ANSWER: D 108. In meter movement, how do you prevent the meter from oscillation and overswing? A. by shorting B. by coupling C. by swamping D. by damping

ANSWER: D 109. When the meter is insufficiently damped, it is considered as A. underdamped B. overdamped C. critically damped D. negatively damped

ANSWER: A 110. A meter when _______ damped will become insensitive to small signals. A. underdamped B. overdamped C. critically damped D. negatively damped

ANSWER: B

Test 7 – Solid State 1. One type of circuit control device which may be manual, automatic or multi-contact A. fuse B. breaker C. switch D. relay ANSWER: B 2. What are the primary methods of controlling electrical power? A. by using manual switches and rheostats B. by using variable reactance and transformers C. by using electronic switches, such as diodes, transistors thyratrons, and thyristors D. all of the above

ANSWER: D 3. Common method(s) of controlling electrical power with reactance A. switching a tapped inductor B. using a saturable reactor

C. by a matching transformer D. A and B above

ANSWER: D 4. A reactive device used in controlling electrical power by using two windings on a common iron core. The control winding is supplied with small dc-current which causes the reactance of large ac-winding to change accordingly. A. tapped inductor B. saturable reactor C. auto transformer D. LVDT

ANSWER: B 5. A saturable reactor with regenerative feedback. A. tapped inductor B. auto transformer C. LVDT D. magnetic amplifier

ANSWER: D 6. Thyratrons in industrial electronics refers to ____________. A. a gas-filled diode B. a vacuum tube C. gas-filled triode D. an electron triode

ANSWER: C 7. An electronic switch that has the highest single-device current capacity and can withstand overloads better. A. Thyristors B. ignitrons C. SCR D. triac

ANSWER: B 8. A semiconductor, electronic switch that has the highest single-device current rating A. thyristor B. triac C. SCR D. Quadric

ANSWER: C 9. The purpose of installing thyrectors across the incoming power lines to the speed control system is to ___________ A. cause the motor to caution B. protect drive circuits from high voltage transient surges C. increase the counter emf D. allow the field winding current to continue flowing

ANSWER: B 10. Semiconductor devices equivalent to thyratrons are generally called A. thyrector B. thyristor C. diac D. ignitron

ANSWER: B 11. Using electronic devices as switches, what is(are) the general methods of controlling electrical power?

A. phase control B. zero-voltage switching C. static switching D. all of the above

ANSWER: D 12. Which power control switching method that greatly generates RFI or EMI and is therefore limited to low-frequency applications? A. phase control B. zero-voltage switching C. inverter control D. static switching

ANSWER: A 13. One of the electronic semiconductor devices known as diac, function as A. four terminal multi-directional switch B. two terminal bi-directional switch C. two terminal unidirectional switch D. three terminal bi-directional switch

ANSWER: B 14. Which of the trigger diodes has the highest holding voltage? A. bidirectional-trigger diac B. bidirectional-diode-thyristor diac C. Shockley diode D. thyrector

ANSWER: A 15. General term of electronic devices used to control or trigger large-power switching devices. A. thyristor B. thyrector C. break-over devices D. triggering devices

ANSWER: C 16. A break-over device that is basically a diode. A. thyristor B. thyrector C. thyratron D. triggering diode

ANSWER: D 17. A four-element solid state device that combi9nes the characteristics of both diodes and transistors A. varactor B. zener diode C. tunnel diode D. SCR

ANSWER: D 18. The most popular thyristor used in electrical power controllers A. SCR B. triac C. SCS D. PUT

ANSWER: A 19. Find the two stable operating conditions of an SCR. A. Conducting and non-conducting

B. Oscillating and quiescent C. NPN conduction and PNP conduction D. Forward conducting and reverse conducting

ANSWER: A 20. How do you stop conduction during which SCR is also conducting? A. remove voltage gate B. increase cathode voltage C. interrupt anode current D. reduce gate current

ANSWER: C 21. How do we turn “ON” or trigger an SCR? A. by making the gate (G) positive with respect to its cathode (K) B. by making the gate (G) positive with respect to its anode (A) C. by making the cathode more positive with respect to the anode D. A and C above

ANSWER: A 22. What is true about SCRs after they are being switched “ON”? A. The anode (A) to cathode (K) continues to conduct even if the gate triggering voltage is removed. B. The gate (G) must be provided with the required holding current to continue its conduction. C. A small holding voltage at the gate is required for a continuous conduction. D. B and C above

ANSWER: A 23. The voltage across the anode (A) and cathode (K) terminals of an SCR when conducting. A. holding voltage B. breakdown voltage C. breakback voltage D. trigger voltage

ANSWER: A 24. The minimum amount of current needed for an SCR to conduct continuously. A. holding current B. triggering current C. threshold current D. average sustaining current

ANSWER: A 25. What is(are) the condition(s) in triggering SCR? A. The gate voltage must be equal to or greater than the triggering voltage. B. The gate current must be equal to or greater than the triggering current. C. The anode (A) must be positive with respect to the cathode. D. all of the above

ANSWER: D 26. The voltage decreased across the anode (A) and cathode (K) of an SCR from non-conducting state to conducting state. A. holding voltage B. forward breakdown voltage C. triggering voltage D. breakback voltage

ANSWER: D 27. An SCR rated 10 A is used as the controlling switch in a circuit powered by 50Vdc. When the SCR fires ON, its anode (A) to cathode (K) voltage was observed

to be 2 V. Calculate the breakback voltage of the SCR. A. 25 Vdc B. 32 Vdc C. 41 Vdc D. 48 Vdc

ANSWER: D

28. The needed voltage at the gate of an SCR before it conducts. A. minimum-gate trigger voltage B. maximum-gate trigger voltage C. minimum-gate peak-inverse voltage D. maximum-gate peak-inverse voltage

ANSWER: A 29. What is(are) the gate limitation(s) of SCRs and triacs? A. maximum-gate power dissipation B. maximum-gate peak-inverse voltage C. maximum-gate trigger current and voltage D. all of the above

ANSWER: D 30. How can we extend the rating of SCRs? A. by external cooling B. by external circuitry C. by connecting them in series/parallel D. all of the above

ANSWER: D 31. Use of heat sinks, forced air, and water cooling are examples of external cooling in SCRs and other devices. Which of these is the only recommended to be used for the largest power dissipating device? A. metal heat sinks B. forced air C. water cooling D. A and B above

ANSWER: C 32. How can we increase the forward-voltage blocking capability of SCRs? A. by connecting them in series B. by connecting them in parallel C. by cascading them D. by connecting back to back in parallel

ANSWER: A 33. In connecting two SCRs in series, during “OFF” state, the voltage source must be properly shared between them, but due to devices’ differences, there might be unequal voltages across each SCR. How do we equalize these voltages? A. by installing a snubber circuit B. by adding a gate-to-cathode resistor C. by shunting a capacitor across the anode (A) and cathode (K) of each SCR D. by using a blocking-equalizing resistor

ANSWER: D 34. What is true regarding blocking-equalizing resistors in SCRs connected in series? A. Blocking-equalizing resistors are shunted across each SCR. B. The value of these resistors is about 10% of the value of the blocking resistance of the SCR it is shunted with. C. These resistors increases the leakage current towards the load.

D. All of the above

ANSWER: D 35. A circuit used for voltage equalization during ON-OFF switching action of SCRs in series. A. snubber circuit B. crow-bar C. clipper D. clamper

ANSWER: A 36. When a high current is needed, SCRs are connected in parallel. The problem with paralleled SCRs is, when they are not perfectly matched, one will conduct first before the other and carries the full-load current that is for sure greater than its maximum rating. To avoid this situation, both SCRs should be turned ON at the same time. How can we do this? A. by using high triggering gate voltage B. by using a gate-triggering transformer C. by using reactors D. all of the above are possible

ANSWER: D 37. In controlling electrical power using phase control method with SCR/triac being the active device, what do we call the period of the cycle before the device switches to conduction? A. trigger time B. trigger delay time C. firing frequency D. firing delay angle

ANSWER: D 38. How many times per second does an SCR is turned ON and OFF when it is operated in a full-wave phase control at a line frequency of 60 Hz? A. 30 times B. 60 times (HV) C. 90 times D. 120 times (FW)

ANSWER: D 39. A three terminal device that behaves roughly like SCR, except that it can conduct current in either direction when at ON. A. thyristor B. SUS C. SBS D. GTO

ANSWER: C 40. What is the difference between a triac and a silicon bilateral switch (SBS)? A. An SBS is usually used as breakover device, while a triac is a load controlling device. B. An SBS is for low voltage applications, while a triac is generally for high voltage applications. C. An SBS has better and stable symmetrical-firing voltage than a triac. D. all of the above

ANSWER: D 41. A triac can be triggered ON by the application of a A. positive voltage at the gate with respect to MT1 B. negative voltage at the gate with respect to MT1

C. positive or negative gate voltage with respect to MT2 D. all of the above are correct

ANSWER: D 42. Which are the three terminals of a TRIAC? A. Gate, anode 1 and anode 2 B. Gate, source and sink C. Base, emitter and collector D. Emitter, base 1 and base 2

ANSWER: A 43. What are the three terminals of a triac? A. anode 1 (A1), anode 2 (A2) and gate (G) B. mainterminal 1 (MT1), mainterminal 2 (MT2), and gate (G) C. anode (A), cathode (K) and gate (G) D. both A and B are acceptable

ANSWER: D 44. A silicon bilateral switch may be considered as s small power triac, and has three terminals namely, A. anode 1 (A1), anode 2 (A2) and gate (G) B. mainterminal 1 (MT1), mainterminal 2 (MT2), and gate (G) C. anode (A), cathode (K) and gate (G) D. both A and B are acceptable

ANSWER: D 45. A thyristor that is very similar to an SCR except that it has low voltage and current ratings. It is very temperature stable, and is therefore suitable to be used as triggering device. A. UJT B. GTO C. SBS D. SUS

ANSWER: D 46. Silicon unilateral switches (SUSs) generally have a breakover voltage of 8 V, however, this value can be altered by normally connecting a zener diode. How is the diode installed? A. across the gate (G) and cathode (K) terminals, with the diode’s anode at the gate B. anode to anode, cathode to cathode C. diode’s cathode to SUS’s anode and diode’s anode to SUS’s cathode D. diode’s cathode to SUS’s gate and diode’s anode to SUS’s cathode

ANSWER: D 47. A silicon unilateral switch (SUS) has a forward breakover voltage of 8 V. a zener diode is connected between its gate and cathode terminals with the diode’s cathode at SUS’s gate. If the zener voltage is 3.9 V, what is the new forward breakover voltage of the device? A. 0.49 V B. 2.05 V C. 4.50 V D. 11.9 V

ANSWER: C 48. Thyristor whose characteristic curve closely resembles that of SCR’s and SUS’s, except that its forward breakover voltage (+VBO) is not alterable, for the device has no gate terminal. A. diac B. thyrector

C. UJT D. Shockley diode

ANSWER: D 49. What will happen to the forward breakdown or breakover voltage of SCRs and triacs if the gate current is increased? A. will decrease B. will also increase C. will not change D. will either increase or decrease, it depends on their current coefficient

ANSWER: A 50. A UJT or unijunction transistor is a three terminal breakover-type switching device. Its three terminals are called base 1, base 2, and emitter. Though this is a transistor and has base and emitter terminals, this operates very different from a BJT and is not used as a linear amplifier. Its applications are for A. timers and oscillators B. signal generators C. triggering control for SCRs and triacs D. all of the above

ANSWER: D 51. A UJT has an internal resistances of RB1 = 6 KΩ and RB2 = 3 KΩ, what is its interbase resistance? A. 2 KΩ B. 3 KΩ C. 6 KΩ D. 9 KΩ

ANSWER: D 52. For a unijunction transistor (UJT) to witch ON A. the base 1 voltage should be greater than the peak voltage B. the base 2 voltage should be greater than the peak voltage C. the emitter voltage should be greater than the peak voltage D. the voltage between the emitter and base 1 should be greater than the peak voltage when emitter being more positive

ANSWER: D 53. Semiconductor devices with inherent ON-OFF behavior and has no linear operating regions are called thryistors. Examples are SCRs, triacs, SUSs, SBSs, Shockley diodes, diacs, PUTs, and SCSs. In selecting thyristors for a particular application, which of the statement below is generally desirable? A. thyristors with high current and voltage ratings B. thyristors with high holding current/voltage C. faster thyristors D. thyristors with high breakback-voltage

ANSWER: D 54. Why does thyristors with high breakback voltage desirable? A. it dissipates less power B. it generates less heat C. it is more efficient D. all of the above

ANSWER: D 55. Portion in the welding process interval during which the welding current is flowing is called ____________. A. cool sub-interval B. released interval C. squeeze interval

D. heat sub-interval

ANSWER: D 56. In automatic welding system, basically there are how many intervals? A. 2 B. 5 C. 10 D. 15

ANSWER: B 57. In automatic welding what do you call the first interval wherein the material to be welded are held together? A. squeeze interval B. weld interval C. hold interval D. standby interval

ANSWER: A 58. After the squeeze interval, what comes next in an automatic welding system? A. squeeze interval B. weld interval C. hold interval D. standby interval

ANSWER: B

59. During the welding or weld interval, when a welding current is flowing the system is said to be at A. weld interval B. cool subinterval C. heat subinterval D. hold interval

ANSWER: C 60. The portion of the weld interval during which the current is absent A. cool subinterval B. heat subinterval C. hold interval D. standby interval

ANSWER: A 61. After the welding interval, it goes to _________ interval wherein the electrode pressure is maintained on the metal surfaces. A. cool subinterval B. heat subinterval C. hold interval D. standby interval

ANSWER: C 62. Next to hold interval is __________ interval in automatic welding system. A. squeeze B. cool C. standby D. release

ANSWER: D 63. After the release interval in automatic welding, the system will go to A. cool interval B. squeeze interval C. standby interval

D. hold interval

ANSWER: C 64. Refers to the system that has no feedback and is not self correcting A. Close-loop system B. Coal slurry system C. Feed forward control system D. Open-loop system

ANSWER: D 65. The system is ____________ if a position servo system does not respond to small changes in the input. A. under stabilized B. underdamped C. stabilized D. overdamped

ANSWER: D 66. What is the purpose of using a differential synchro instead of a regular synchro? A. Handles more signals only B. Performs addition and subtraction function only C. Differential synchros can handle more signals and also performs addition and subtraction function D. Handles two signals only

ANSWER: C 67. Industrial circuit or system that is not self-correcting A. open-loop B. closed-loop C. system with feed back D. non-servo

ANSWER: A 68. What do you call a circuit or system that is self-correcting? A. open-loop B. closed-loop C. system without feed back D. servo

ANSWER: B 69. Open-loop in control system means: A. it has no feedback B. it is not self-correcting C. it is not self-regulating D. all are correct

ANSWER: D 70. In control system, closed-loop means: A. it has feedback B. it is self-correcting C. it is self-regulating D. all are correct

ANSWER: D 71. When a closed-loop system is used to maintain physical position it is referred as A. gyro system B. feedback system C. servo system

D. differential system

ANSWER: C 72. In closed-loop system, what do you call the difference in the measured value and the set value or desired value? A. error B. differential voltage C. potential difference D. threshold

ANSWER: A

73. Error signal in closed-system is also known as A. difference signal B. deviation C. system deviation D. all are correct

ANSWER: D 74. In a closed-loop control system, when the error signal is zero the system is at A. null B. saturation C. cut-off D. halt

ANSWER: A 75. The small error signal or system deviation where the system cannot correct anymore A. threshold B. holding C. offset D. bias

ANSWER; C 76. A good closed-loop control system has the following characteristics A. with very small offset signal or voltage B. quick response C. highly stable D. all are correct

ANSWER: D 77. In control system, the manner in which the controller reacts to an error is termed as A. mode of operation B. type of operation C. mode of control D. reaction style

ANSWER: C 78. What are the general basic modes of control in control system? A. On-Off B. Proportional C. Proportional plus integral D. Proportional plus derivative

ANSWER: D 79. Mode of control wherein the controller has only two operating states. This mode is also known as bang-bang control. A. On-Off

B. Proportional C. Proportional plus integral D. Proportional plus derivative

ANSWER: A 80. ____________ is a mode of control wherein the controller has a continuous range of possible position, not just two as in bang-bang control. A. On-Off B. Proportional C. Proportional plus integral D. Proportional plus derivative

ANSWER: B 81. Proportional mode of control wherein the controller is not only considering the magnitude of the error signal but as well as the time that is has persisted. A. On-Off B. Proportional C. Proportional plus integral * D. Proportional plus derivative

ANSWER: C 82. Proportional mode of control wherein the controller is not only considering the magnitude of the error signal but as well as its rate of change. A. Proportional B. Proportional plus integral C. Proportional plus derivative * D. Proportional plus integral plus derivative

ANSWER: C 83. What is (are) being considered in Proportional plus Integral plus Derivative (PID) mode of control? A. error signal magnitude B. error signal period of occurrence C. error signal rate of change D. all are considered *

ANSWER: D 84. If On-Off mode of control is the simplest, what is its opposite or the most complex? A. Proportional B. Proportional plus integral C. Proportional plus derivative D. Proportional plus integral plus derivative *

ANSWER: D 85. The __________ are two of the most common mechanical configuration of industrial robots. A. Spherical and pneumatic B. Articulated arm and cylindrical * C. Spherical and hydraulic D. Jointed-arm and electric

ANSWER: B 86. One advantage of hydraulic actuator in industrial robots include _____________. A. great force capability handling heavy loads * B. lower operating cost than the other type C. low initial cost than the other type D. clean-no oil leaks

ANSWER: A 87. ____________ includes tow of the actuator type used in industrial robots. A. Pneumatic and Jointed-arm B. Hydraulic and Pneumatic C. Electric and Spherical D. Hydraulic and Cylindrical

ANSWER: B 88. A system in which the precise movement of a large load is controlled by a relatively weak signal. A. hydraulic B. electro C. synchro D. servo

ANSWER: D 89. A programmable, multifunction manipulator designed to move materials, parts, tools or specific devices. A. Industrial robot B. Android C. Actuator D. End effector

ANSWER: A 90. The technology for automations A. avionics B. cryogenics C. cryotronics D. robotics

ANSWER: D 91. What is(are) the common mechanical configurations for industrial robots? A. articulated-arm or jointed-arm B. spherical configuration C. cylindrical configuration D. all of these

ANSWER: D 92. The number of axis a robot is free to move is called A. freedom axis B. degrees of freedom C. movement degrees D. mechanical axis

ANSWER: B 93. Actuators used in industrial robots A. electric motors B. fluid motors C. fluid cylinders D. all of these are correct

ANSWER: D 94. Which of the actuators that has the greatest force capability? A. electric B. hydraulic fluid C. pneumatic D. magnetic

ANSWER: B

95. Actuator that requires the highest initial cost: A. electric B. hydraulic C. pneumatic D. magnetic

ANSWER: B 96. Robot actuator that has the highest operating cost: A. electric B. hydraulic C. pneumatic D. magnetic

ANSWER: B 97. The most messy robot actuator: A. electric B. hydraulic C. pneumatic D. magnetic

ANSWER: B 98. Advantages of electric actuators: A. Lower initial cost than either hydraulic or pneumatic B. Much lower operating cost than hydraulic C. Accurate positioning and good velocity control D. All of these are correct

ANSWER: D 99. Advantages of pneumatic actuators: A. lower initial and operating cost than hydraulic actuators B. Clean, no oil leaks C. Quick response D. All are correct

ANSWER: D 100. Advantages of hydraulic actuators A. Great holding strength when stopped B. Accurate positioning and good velocity control C. Intrinsically safe in flammable environment such as painting D. All of these are correct

ANSWER: D

101. Disadvantages of pneumatic actuators: A. Weak force capability B. Not so much holding strength when stopped as compared to hydraulic system C. Accurate positioning and velocity control is impossible D. All of these are correct

ANSWER: D 102. Disadvantages of electric actuators in industrial robots: A. Less force capability as compared to hydraulic system B. Very little holding strength when stopped which causes a heavy load to sag C. Usually requires mechanical brakes D. All are correct

ANSWER: D 103. A robot software or program that produces only two-position motion for a given robot axis.

A. positive-stop B. point-to-point C. continuous-path D. hard interrupt

ANSWER: A 104. A robot program that has the ability to move a robot to any position within the range but without specific path. A. positive-stop program B. point-to-point program C. continuous path program D. compound program

ANSWER: B 105. A robot program that has the ability to move a robot to any position within the range with specific path. A. positive-stop program B. point-to-point program C. continuous path program D. compound program

ANSWER: C 106. When a robot moves on several axis at the same time, it is to have A. intrinsic motion B. extrinsic motion C. compound motion D. universal motion

ANSWER: C 107. In robotics, SCARA means: A. Selective Compliant Articulated Robot Arm B. Selective Compliant Assembly Robot Arm C. Selective Computer-Actuated Robot Arm D. A and B are correct

ANSWER: D 108. SCARA Robots has how many axis of motion? A. 2 B. 4 C. 6 D. 8

ANSWER: B 109. SCARA Robots are designed for what applications? A. Machining B. Welding C. Assembling D. Handling heavy loads

ANSWER: C 110. Why is SCARA Robot attractive in industry? A. because it is relatively cheaper B. because it can carry very heavy loads C. because it has unlimited movement D. all of the above

ANSWER: A

Test 8 – Computers

1. An English mathematician who invented the slide rule in 1622. A. Blaise Pascal B. Clifford Berry C. Charges Babage D. William Oughtred

ANSWER: D 2. Built a computer in 1946 at the Institute of Advance Study (IAS), Princeton, USA, that uses binary numbers and stores information. A. Vannevar Bush B. John Van Neumann C. John Atannasoff D. Clifford Berry

ANSWER: B 3. An electronic device design to accept data performs prescribed computational and logical operations at high speed and output the results of this operation. A. Compiler B. Simulator C. Computer D. Digital machine

ANSWER: C 4. First commercial computer introduce in 1953 that uses valves. A. IBM-1400 B. UNIVAC C. IBM-701 D. ENIAC

ANSWER: B 5. The first electronic computer and was completed in 1946. A. ENIAC B. UNIVAC C. EDVAC D. Whirlwind I

ANSWER: A 6. ENIAC was developed at A. University of Pennsylvania B. Massachusetts Institute of Technology C. Cambridge University D. Bell Laboratories

ANSWER: A 7. Who constructed ENIAC and UNIVAC? A. William Oughtred B. Presper Eckert and John W. Mauchly C. John von Neumann D. William Oughtred and Jon von Neumann

ANSWER: B

8. ENIAC consist of how many vacuum tubes? A. 1,500 tubes B. 3,575 tubes C. 13,575 tubes D. 18,000 tubes

ANSWER: D 9. ENIAC could perform _________ additions or up to _________ multiplications pe

r second. A. 1,000 / 100 B. 1,500 / 150 C. 3,000 / 300 D. 5,000 / 500

ANSWER: D 10. Whirlwind I, develop at Massachusetts Institute of Technology is capable of _________ operations per second. A. 1,000 B. 5,000 C. 10,000 D. 20,000

ANSWER: D 11. Refers to the increased use of data conversion circuits as a result of increased application. A. Op Amps B. Linear circuit C. Computers D. Digital equipment

ANSWER: C 12. What is a group of circuits that provides timing and signals to all operations in the computer? A. Output unit B. Memory unit C. Control unit D. Input unit

ANSWER: C 13. Refers to the part of computer that performs mathematical operations. A. CPU B. Flip-flop C. Assembly language D. ALU

ANSWER: D 14. What does ALU which carries arithmetic and logic operations process? A. Binary coded decimal B. Hexadecimal numbers C. Octal numbers D. Binary numbers

ANSWER: D 15. What is the smallest part of a computer language? A. binary B. byte C. bit D. word

ANSWER: C 16. A digital word consisting of only four bits is called a A. dibit B. quad C. pixel D. nibble

ANSWER: D 17. Electronics methodology in solving application problems using circuits, in w

hich there are only two possible voltage levels. A. digital electronics B. switching techniques C. state diagramming D. bistable electronics

ANSWER: A 18. In digital electronics, there are mainly two possible voltage levels and these make _____ number system to be useful in its analysis. A. binary B. octal C. hexadecimal D. all of the above ANSWER: A 19. 1 and 0 in binary number system are used to represent the two different voltage levels or logic levels in digital circuits. However, in most applications, a long string of 1’s and 0’s occur, and makes the data presentation “nasty”. To condense this long string of 1’s and 0’s, the ___________ number system is (are) also used. A. octal B. decimal C. hexadecimal D. all of the above

ANSWER: D 20. How many symbols are used in octal digital number system? A. 16 B. 4 C. 8 D. 2

ANSWER: C 21. How many symbols does hexadecimal digital number system used? A. 16 B. 4 C. 8 D. 32

ANSWER: A 22. What is the equivalent of decimal number 11 in binary? A. 1101 B. 1110 C. 1111 D. 1011

ANSWER: D 23. Which of the following is not used in hexadecimal digital symbols? A. A B. C C. H D. F

ANSWER: C 24. What is the equivalent of decimal 7 in octal? A. 21 B. 49 C. 7 D. 14

ANSWER: C 25. The decimal 36020 is equivalent to hexadecimal ___________.

A. 8CB4 B. 88BC C. 8BC8 D. 884C

ANSWER: A 26. What is the equivalent of decimal 14 in binary? A. 1110 B. 1011 C. 1101 D. 1111

ANSWER: A 27. The code 1011 in BCD is A. 24 B. Letter A C. 11 D. Invalid

ANSWER: D 28. Conversion from binary to octal number system needs a grouping of bits by A. Two B. Three C. Four D. Five

ANSWER: B 29. Convert the given binary number 1010011.01 to octal system. A. 511.1 B. 511.2 C. 123.1 D. 123.2

ANSWER: D 30. What is the hexadecimal equivalent of the binary number 1010011.01? A. 53.4 B. 53.1 C. A6.1 D. A6.4

ANSWER: A 31. The most practical way of converting hexadecimal numbers to binary is to give each number its _________ equivalent bits. A. Two B. Three C. Four D. Five

ANSWER: C 32. The binary equivalent of the hexadecimal number ECE.5 A. 1110 1100 1110.0101 B. 1110 1100 1110.101 C. 1101 1100 1101.101 D. 1101 1100 1101.0101

ANSWER: A 33. Convert (1111 1111 1111 1111)2 to decimal number. A. 32 767 B. 32 768 C. 65 535

D. 65 536

ANSWER: C 34. Find the sum of binary number 1010 and 0011. A. 1021 B. 1101 C. 1011 D. 1111

ANSWER: B 35. Get the sum of (110.1101)2 and (11.01)2. A. 1010.0101 B. 1010.0001 C. 1101.0101 D. 0111.1010

ANSWER: B 36. What is the difference between the given binary numbers, 110.1101 and 11.01? A. 110.0000 B. 111.1010 C. 11.1010 D. 11.1001

ANSWER: D 37. Find the radix-minus one complement of (110.1101)2. A. 111.0010 B. 010.0011 C. 1.001 D. 001.0010

ANSWER: D 38. Give the true complements of (1101.1100)2. A. 0010.0011 B. 10.0011 C. 10.01 D. 0010.0100

ANSWER: D 39. Mathematics used in expressing, analyzing, and designing of digital electronic circuits. A. Boolean algebra B. Numerical methods C. Statistical approach D. Logical mathematics

ANSWER: A 40. Method(s) used in simplifying Boolean algebra. A. Karnaugh map B. Map-entered variable technique C. Quine-McCluskey tabular method D. All of the above

ANSWER: D 41. Karnaugh map is the most commonly used method in simplifying Boolean expression or logical functions. In this method only 1’s and 0’s are entered into the table, while ________ includes variables into the table. A. Boolean algebra B. Map-entered variable technique C. Superposition method

D. Quine-McCluskey tabular method

ANSWER: B 42. A suitable method in simplifying Boolean expression when the system deals with more than six variables. A. Boolean algebra B. Karnaugh map C. Map-entered variable technique D. Quine-McCluskey tabular method

ANSWER: D 43. What level is used to represent logic 1 in a negative logic circuit? A. negative transition level B. low level C. positive transition level D. high level

ANSWER: B 44. What level is used to represent logic “0” in a negative logic circuit? A. high level B. low level C. negative transition level D. positive transition level

ANSWER: A 45. _________ is a gate which has two or more low inputs signals to get a low output. A. AND B. Inverter C. OR D. NAND

ANSWER: C 46. What is the logic circuit having two or more inputs but only output, with high output of any or all inputs are high, with low output only if all inputs are low? A. AND gate B. OR gate C. NOR gate D. NAND gate

ANSWER: B 47. A logic gate whose output is HIGH when a single HIGH at its input is present. A. OR gate B. NOR gate C. AND gate D. NAND gate

ANSWER: A 48. An output of logic zero can be generated by what logic gate(s) if all inputs are zero? A. OR gate B. AND gate C. NOR gate D. NAND gate

ANSWER: A 49. Logic gate that generates an output of logic zero if and only if all inputs are zero.

A. OR gate B. AND gate C. NOR gate D. NAND gate

ANSWER: A 50. A solid state device which only gives a “1” output if all inputs are also “1” is called A. an AND gate B. a NAND gate C. a NOR gate D. an OR gate

ANSWER: A 51. Only when all inputs are logic one that this gate can delver an output of logic one. A. NOR gate B. AND gate C. NAND gate D. XOR gate

ANSWER: B 52. A solid state logical device which only gives a “1” output if all inputs are “0” is called a _________ gate. A. NOT B. NOR C. NAND D. OR

ANSWER: B 53. To cause a three-state buffer to output 0-1 levels, the following must be true: A. The output enable must be false B. The output enable must be true C. The information must have been stored in the buffer D. The signal OE must be at logic 1

ANSWER: D 54. The rapidly flashing logic probe tip tells you that the logic node being probe A. Has rapidly changing logic activity B. Is struck C. Is at an illegal logic level D. Has an unstable logic activity

ANSWER: A 55. ______________ is a single bit comparator. A. Wired OR B. Exclusive OR C. NOR gate D. Exclusive NOR

ANSWER: D 56. _____________ refers to the class of logic circuit containing flip-flops. A. Combinational B. Sequential C. Linear D. Feedback

ANSWER: B

57. What is the counter that follows the binary sequence? A. Binary counter B. Simplex counter C. Shift counter D. Decimal counter

ANSWER: A 58. What logic circuit is analogous to a single pole mechanical selector switch? A. Decoder B. Encoder C. Multiplexer D. Exclusive OR

ANSWER: C 59. An encoder is an MSI (medium-scale-integrated) circuit that A. Provides an output code that corresponds to which of a set of input line is true B. Provides a storage of a certain number of binary bits C. Selects a given output based on binary input code D. Provides for delivering one of two or more inputs to an output

ANSWER: A 60. _____________ is called the time sharing of one line with multiplex signals. A. Simultaneous transmission B. Bi-directional C. Relay D. Multiplexing

ANSWER: D 61. Data selector is also called A. Encoder B. Decoder C. Multiplexer D. Demultiplexer

ANSWER: C 62. _____________ refers to a function of a decade counter digital IC. A. Provides one output pulse for every 10 inputs pulses B. Adding two decimal numbers C. Producing 10 output pulses for every 1 pulse D. Decoding a decimal number for display on seven-segment

ANSWER: A 63. ___________ refers to BCD counter: A. Decade counter B. Shift register C. Frequency divider D. Binary counter

ANSWER: A 64. In a system with MOS devices, the main bus loading factor is likely to be

A. Resistive B. Current C. Capacitive D. Static charge

ANSWER: C 65. When a logic circuit rejects an unwanted signal, this is termed as ___________. A. Logic levels B. Noise margin C. Power consumption D. Propagation delay

ANSWER: B 66. Speed of a logic circuit is normally expressed as _________. A. Logic levels B. Speed immunity C. Propagation delay D. Power consumption

ANSWER: C 67. What is a multi-wire connection between digital circuits? A. Bus B. Wire wrap C. Multiplexed cable D. Cable ribbon

ANSWER: A 68. What is the process used to describe analog-to-digital conversion? A. Binarize B. Linearize C. Digitize D. Analogize

ANSWER: C 69. What is the process of converting multiple analog input signals sequentially to digital output? A. Time division multiplexing B. Analog to digital conversion C. Space division multiplexing D. Pulse code modulation

ANSWER: A 70. What do you call a circuit that changes pure binary code into ASCII? A. Decoder B. Encoder C. Demultiplexer D. Code converter

ANSWER: D 71. The output pulses of the logic pulser _________. A. Can damage logic circuits B. Are too many for the logic probe to respond to C. Can only force high nodes to low D. Can be used to overdrive logic nodes high or low

ANSWER: D 72. Circuits used to implement Boolean expression or equations. A. Logic gates/circuits B. Digital circuits C. Binary circuits D. All of the above

ANSWER: D

73. Logic gate whose output is HIGH when one or all of its inputs is LOW. A. OR gate B. NOR gate C. AND gate D. NAND gate

ANSWER: D 74. What logic gate that generates an output of logic zero (LOW) only when all its inputs are logic one (HIGH)? A. OR gate B. NOR gate C. AND gate D. NAND gate

ANSWER: D 75. Only when all inputs are LOW thus, this logic gate produces an output of HIGH. A. NOR gate B. NAND gate C. AND gate D. NOR and NAND

ANSWER: A 76. A logic gate whose output is logic zero every time one of its inputs goes to logic one. A. NOR gate B. NAND gate C. XOR gate D. A and C

ANSWER: A 77. Gate with HIGH output level every time one of its inputs goes LOW. A. NOR gate B. NAND gate C. XNOR gate D. B and C

ANSWER: B 78. What logic gate that gives an output of logic one if there is an odd number of 1’s at the input? A. NOR gate B. NAND gate C. XOR gate D. XNOR gate

ANSWER: C 79. Logic gate that gives a HIGH output when the input has an even number of 1’s. A. NOR B. NAND C. XOR D. XNOR

ANSWER: D 80. A circuit that converts the input logic level to its complement. A. Inverter B. NOR gate with all inputs tied C. NAND gate with all inputs tied D. All of the above

ANSWER: D

81. If the fan out of a logic gate is not enough, a/an ___________ should be used. A. Inverter B. Amplifier C. Buffer D. Isolator

ANSWER: C 82. A buffer multiplies the number of gates a certain output can drive, and this can also be used as a/an A. Voltage follower B. Current amplifier C. Isolator D. All of the above are correct

ANSWER: D 83. Is considered as a controlled inverter. A. XOR B. NOR C. NAND D. AND

ANSWER: A 84. A logic gate that can be wired to function like any other gate. A. International gate B. Flexible gate C. Variable gate D. Universal gate

ANSWER: D 85. Known as universal gates. A. OR and AND B. AND and NAND C. OR and NOR D. NOR and NAND

ANSWER: D 86. How many NAND-gates are needed to have an AND function? A. 2 B. 3 C. 4 D. 5

ANSWER: A 87. The number of NAND-gates needed to form an OT-gate. A. 2 B. 3 C. 4 D. 5

ANSWER: B 88. OR function can be achieved by suing how many NOR gates? A. 2 B. 3 C. 4 D. 5

ANSWER: A 89. Which of the following is the probable output if all inputs of a TTL gate are binary 1?

A. Determinable B. Binary 0 C. Binary 1 D. Indeterminate

ANSWER: B 90. Logic devices are broadly divided or categorized into two families, bipolar and MOS. What are the examples of bipolar? A. RTL and DTL B. IIL and ECL C. TTL and HLDTL D. All of the above

ANSWER: D 91. CMOS, NMOS, and PMOS belong to MOS family, what is (are) the significance of these devices? A. They have lower power dissipation than bipolar devices B. They are generally slower than bipolar devices C. They are most sensitive to electrostatic D. All of the above

ANSWER: D 92. Refers to the ability of logic circuit it withstand noise superimposed on its input signal. A. LOW noise immunity B. HIGH noise immunity C. Noise immunity D. Noise figure

ANSWER: C 93. The number of logic gates of the same family that can be connected to the input of a particular gate without degrading the circuit performance. A. Fan-in B. Fan-out C. Input-drive D. Input noise immunity

ANSWER: A 94. Refers to the number of logic gate of the same family that can be driven by a single output of a particular logic gate. A. Output drive B. Output noise margin C. Fan-in D. Fan-out

ANSWER: D 95. A bipolar logic family that uses resistors as its input circuit. A. RTL B. DTL C. ECL D. TTL

ANSWER: A 96. Logic family that uses diodes and transistors as its circuit elements. This logic family is more resistant to noise than RTL. A. DTL B. TTL C. ECL D. I2L or IIL

ANSWER: A 97. A logic circuit family with a supply voltage of 25 V, and are generally used in industry where machinery causes electrical noise and large power line transients to occur. A. HLDTL B. 74HXX C. NMOS D. CMOS

ANSWER: A 98. A variation of transistor-transistor-logic (TTL) wherein transistor’s base and collector junctions are clamped with a Schottky diode. A. ECL B. STTL C. I2L D. CML

ANSWER: B

99. In a transistor-transistor logic (TTL), if the base collector junction of a transistor is clamped with a Schottky diode it becomes Schottky TTL. What is the significance of having this diode? A. It increases the switching speed B. It decreases the power dissipation C. It increases the noise margin D. It increases the fan-out

ANSWER: A 100. Which of the bipolar logic circuits is the fastest? A. TTL B. STTL C. SCTL D. ECL

ANSWER: D 101. Other name of emitter-coupled logic (ECL). A. CML B. CSL C. NSL D. All of the above

ANSWER: D 102. Of all bipolar logic families, TTL is widely used. What do you think is (are) the reason(s) why? A. Its speed is just enough for most applications B. Its power consumption/dissipation is manageable C. It has a good noise immunity D. All of the above

ANSWER: D 103. Of the MOS logic family, which is the fastest? A. PMOS B. NMOS C. CMOS D. VMOS

ANSWER: C 104. PMOS are generally supplied with a voltage up to A. 5.5 V B. 12 V

C. 15 V D. 24 V

ANSWER: D 105. CMOS are normally supplied a voltage up to what value? A. 5.5 V B. 12 V C. 15 V D. 24 V

ANSWER: C

106. PMOS and CMOS have normally different supply requirements. However, both can be operated from the same power supply provided it should be up to the CMOS limitation (15 V). CMOS output can drive directly PMOS inputs, but not PMOS’s output to CMOS’s input. How do you interface PMOS to CMOS? A. By providing a pull-down resistor at the interconnection (PMOS output to CMOS input) B. By providing a pull-up resistor at the interface C. By inserting a series limiting resistor between PMOS output and CMOS input D. By interfacing through an open-collector transistor configuration

ANSWER: A 107. NMOS can be interfaced to CMOS by providing a A. Pull-up resistor B. Pull-down resistor C. Limiting resistor D. Coupling capacitor

ANSWER: A 108. A digital IC whose output transistor has no internal pull-up resistor. A. Open-collector configuration B. Open-emitter configuration C. Totem-pole output D. Tri-sate output

ANSWER: A 109. In digital ICs, such as buffers and registers, what output configuration is used if they are intended for “busing”? A. Totem-pole B. Tri-state output C. Complementary D. Open-collector

ANSWER: B 110. The output configuration of most CMOS ICs. A. Totem-pole B. Open-source C. Darlington D. Complementary

ANSWER: D 111. In TTL ICs, which input configurations gives a high-input impedance at both logic states (HIGH and LOW state)? A. MET B. Input with kicker transistor C. Diode cluster input D. Substrate PNP input

ANSWER: D

112. What is the purpose of the internal clamping diodes at the input of a logic circuit? A. To minimize negative ringing effects B. To minimize positive ringing effects C. To regulate the input signal D. To protect reverse-polarity connection

ANSWER: A 113. In TTL ICs with more than one gate available, sometimes not all gates are used. How ill you handle these unused gates? A. Force the output to go LOW B. Force the output to go HIGH C. Provide pull-down resistors to all inputs D. Provide all inputs with pull-up resistors

ANSWER: B 114. How ill you handle unused inputs in a logic gate/ logic IC? A. Leave them floating B. Pull them down C. Pull them up D. Pull them down or up, depending on circuit function

ANSWER: D 115. What is the memory element used in clocked sequential logic circuit? A. Gates B. Flip-flop C. Static-RAM D. Read-only memory

ANSWER: B 116. A static memory will store information A. As long as power is applied to the memory B. Even when power is not applied to the memory C. As long as power is applied and the memory is refreshed periodically D. When power is applied at regular intervals

ANSWER: B 117. What is the reason why more cells can be stored in a given area with dynamic cells? A. They consume less power B. They are similar C. They are larger D. They travel faster

ANSWER: B 118. A ______________ is a solid state memory device, which depends on the magnetic polarization of domains, usually in a garnet type material. A. Magnetic disk B. Magnetic core C. Magnetic bubble D. Magnetic drum

ANSWER: C 119. ______________ are non-semiconductor devices still used in digital memories. A. Gates B. Flip-flops C. Relay D. Magnetic cores

ANSWER: D 120. The density of data recorded on magnetic tape is measured in A. Bit stuffing rate B. Bit error rate C. Bits per inch D. Bits per second

ANSWER: C 121. A memory circuit that has 9 address inputs has how many storage locations? A. 1024 B. 256 C. 512 D. Not determined by sets of input

ANSWER: C 122. Clock periods are measured from ___________. A. The high level to the low level B. The low level to the high level C. Similar points on the clock waveform D. The clock pulse at 50% of its low or high levels

ANSWER: C 123. Determine which item is not a storage device. A. Card readers B. CD-ROM C. Diskettes D. Magnetic tape

ANSWER: A 124. What is the function of flip-flop as logic element? A. Stores binary data B. Generates clock signal C. Relay data D. Makes decision

ANSWER: A 125. _____________ is not a type of flip-flop. A. RS B. Latch C. D D. Register

ANSWER: D 126. What is the higher voltage level in digital gates and flip-flop circuits? A. Yes or One B. One or Zero C. Zero or No D. Yes or No

ANSWER: A 127. _____________ is a byte data stored in a memory location. A. 8 bits B. Character C. 4 bits D. Memory word

ANSWER: D 128. _____________ is called retrieving data from memory. A. Accessing B. Getting

C. Encoding D. Reading

ANSWER: A 129. ____________ can erase EPROMS. A. Applying a 21-volt pulse B. Applying ultraviolet rays C. Turning off the power D. Blowing fuse

ANSWER: B 130. ___________ is a segment register which normalcy access variables in the program. A. Extra B. Stack C. Data D. Code

ANSWER: B 131. ____________ is a storage device used to accommodate a difference in rate of flow of data or time of occurrence of events when transmitting from one device to another. A. Accumulator B. Buffer C. Modem D. Register

ANSWER: B 132. _____________ is a device that stay on once triggered and store one or two conditions as a digital circuit. A. Gate B. Latch C. Integrator D. Oscillator

ANSWER: B 133. The typical number of bits per dynamic memory location is A. 1 B. 8 C. 2 D. 16

ANSWER: A 134. ______________ is an output applied to Read Only Memory (ROM). A. Multiplexer B. Address C. Input code D. Data

ANSWER: B 135. ____________ is a kind of memory where only manufacture can store program and has s group of memory locations each permanently storing a word. A. ROM B. SOS memory C. RAM D. Hard memory

ANSWER: A 136. In shift registers made up of several flip-flops, the clock signal indicates ________.

A. A bit of information stored in flip-flop B. Information of time C. What time is it D. When to shift a bit of data from input of the flip-flop to the output

ANSWER: D 137. What do you call the duration within it takes to read the content of a memory location after it has been addressed? A. Execution time B. Data rate C. Cycle time D. Access time

ANSWER: D 138. A static memory generally contains A. Row and column decoders B. No decoders C. Row decoders D. Column decoders

ANSWER: A 139. ___________ is called a memory device which holds fixed set of data in a circuit. A. RAM B. Register C. Logic D. ROM

ANSWER: D 140. An interval required to address and read out memory word. A. Propagation delay B. Pulse duration C. Setting time

D. Access time

ANSWER: D 141. ___________ refers to a circuit that stores pulses and produces an output pulse when specified numbers of pulses are stored. A. Counter B. Register C. Flip-flop D. Buffer

ANSWER: A 142. A dynamic memory will store information A. As long as power is applied to the memory B. As long as power is applied and the memory is refreshed periodically C. Even when power is not applied to the memory D. When power is applied at regular interval

ANSWER: B 143. Several gates combined to form the basic memory element. A. Multivibrator B. Register C. ROM D. Flip-flop

ANSWER: D

144. An RS flip-flop constructed from NOR-gates would have an undefined output when the inputs R/S combinations are A. LOW / LOW B. LOW / HIGH C. HIGH / LOW D. HIGH / HIGH

ANSWER: D 145. When a flip-flop is constructed from two NAND-gates, its output will be undefined if the R/S inputs are A. LOW / LOW B. LOW / HIGH C. HIGH / LOW D. HIGH / HIGH

ANSWER: A 146. A flip-flop whose output is always the same as its input. This is sometimes used as delay element. A. RS flip-flop B. D flip-flop C. T flip-flop D. JK flip-flop

ANSWER: B 147. Flip-flop that changes state every time the input is triggered. A. RS flip-flop B. Master slave flip-flop C. T flip-flop D. JK flip-flop

ANSWER: C 148. Flip-flop arrangement, such that the first receives its input on the positive edge of a clock pulse, and the other receives its input from the output of the first during the negative edge of the same pulse. A. Clocked RS flip-flop B. Clocked JK flip-flop C. Cascaded flip-flop D. Master/slave flip-flop

ANSWER: D 149. Combination of flip-flop, arranged so that they can be triggered at the same time. A. Clocked flip-flop B. Delayed flip-flop C. Sequential flip-flop D. Asynchronous flip-flop

ANSWER: A 150. A flip-flop without an undefined output state condition whatever the input combination is A. JK flip-flop B. T flip-flop C. D flip-flop D. All of the above

ANSWER: D 151. Group of flip-flops used to store more bits. A. Register B. ROM C. PROM

D. All of the above

ANSWER: A 152. Sequential access digital memory uses what storage circuit? A. Parallel register B. Shift register C. Dynamic RAM D. EEPROM

ANSWER: B 153. Memory whose contents are lost when, electrical power is removed. A. Nonvolatile B. Temporary C. Dynamic D. Volatile

ANSWER: D 154. One of the following can program PROMs. A. Biasing bipolar transistor B. Blowing fuse C. Effusing input D. Charging a gate

ANSWER: B 155. Type of memory wherein the data are permanently stored. Usually the storing of data is done during manufacturing of the component. A. ROM B. PROM C. EPROM D. EEPROM

ANSWER: A 156. A semiconductor memory device in which data can be stored after fabrications. A. PROM B. EPROM C. EEPROM D. All of the above

ANSWER: D 157. A type of ROM that allows data to be written into the device by a programmer. After it has been programmed it cannot be reprogrammed again. A. PROM B. EPROM C. EEPROM D. A and B above

ANSWER: A 158. What memory device that can be programmed, and reprogrammed after the old programs are erased usually by an ultraviolet light? A. EEPROM B. EPROM C. RPROM D. B and C

ANSWER: D 159. A variation of PROM, wherein its stored data can be erased by electrical signal instead of ultraviolet light. A. EEPROM B. Dynamic ROM

C. RAM D. EEPROM and dynamic RAM

ANSWER: A 160. A nonvolatile memory A. ROM B. PROM and RPROM C. EPROM and EEPROM D. All are correct

ANSWER: D 161. What is the time interval to undertake a refresh operation in a typical dynamic RAM? A. 2 ms B. 200 ms C. 50 microsec. D. 22 microsec.

ANSWER: A 162. Semiconductor-based, volatile data storage device that can be written and read randomly. A. RAM B. PROM C. EPROM D. EEPROM

ANSWER: A 163. Random access memory that needs recharging of capacitors. A. SRAM B. DRAM C. Dynamic storage D. A and B

ANSWER: B 164. Dynamic RAM (DRAM) uses capacitor as its data storage element, while static RAM (SRAM) uses what? A. Inductor B. Magnet C. Register D. Flip-flop

ANSWER: D 165. Type of memory that is formed by a series of magnetic bubbles at the substrate. A. Magnetic disk B. Bubble sort C. Bubble chart D. Bubble memory ANSWER: D 166. Non-semiconductor digital memory device. A. Magnetic core B. Magnetic domain C. Saturable core D. Ferromagnetic domain

ANSWER: A 167. A hardware used to program a PROM. A. Microcomputer B. Data loader C. Encoder

D. PROM programmer

ANSWER: D 168. Computer hardware device constructed to perform shifting of its contained data. A. Parallel register B. Serial to parallel register C. Shift register D. ALU

ANSWER: C 169. Register wherein data can be serially inputted, while the output can be retrieved in parallel manner. A. Serial to parallel register B. Parallel storage C. Parallel to serial register D. Serial register

ANSWER: A 170. Digital device similar to that of a ROM and whose internal connections of logic arrays can be programmed by passing high current through fusible links. A. PLA B. PAL C. APL D. A and B

ANSWER: D 171. What is the difference between a read only memory (ROM) and a programmable logic array (PLA)? A. All input combinations of a ROM produce an output, while in a PLA, some input combinations do not affect the output. B. Only the OR-functions in a ROM are programmable, whereas in a PLA, both OR and AND-functions are programmable. C. In ROM, all the possible states must be programmed, while not all for a PLA. D. All of the above

ANSWER: D 172. The difference between a programmable logic array (PLA) and a programmable array logic (PAL) is that, A. With PLA, only OR-gates are programmable, whereas both OR and AND gates are programmable in PAL B. With PLA, both OR and AND-gates are programmable, while in PAL only OR-gate is programmable C. With PLA, both OR and AND-gates are programmable, while in PAL, only AND-gate is programmable D. Only AND-gate is programmable with PLA, whereas both OR and AND-gates are programmable for PAL

ANSWER: C 173. A circuit used for selecting a single output from multiple inputs. A. Universal logic module (ULM) B. Demultiplexer C. Tri-state D. Logic array

ANSWER: A 174. Another name for universal logic module (ULM) A. Multiplexer B. Decoder C. Coder

D. Shift register

ANSWER: A 175. A device/circuit used to separate two or more signals from one line. A. Decoder B. Demodulation C. Demodifier D. Demultiplexer

ANSWER: D 176. An electronic counter in which bistable units are cascaded to form a loop. A. Ring counter B. Twisted ring counter C. UP/DOWN counter D. Bistable counter

ANSWER: A 177. What is formed when the complemented output of the last stage of a shift register is fed back to the input of the first stage? A. Ring counter B. Twisted ring counter C. Decade counter D. UP/DOWN counter

ANSWER: B 178. A digital circuit that produces logic 1 output pulse for every 10 input pulses. A. Decade scaler B. Divider C. Chopper D. Multiplexer

ANSWER: A 179. Binary codes are converted into ASCII by what circuit? A. Decoder B. Demultiplexer C. Degenerator D. Code converter

ANSWER: D 180. The technical term used when signals are converted from analog-to-digital. A. Digitize B. Quantize C. Coded D. All of the above

ANSWER: A 181. ________________ is a sequence of instructions that tells the computer machine on how available data shall be processed. A. Program B. RAM C. Command D. Flowchart

ANSWER: A 182. Diagram showing procedures that are followed, and actions taken is called A. Functional block diagram B. Circuit diagram C. Flow chart D. Schematic diagram

ANSWER: C 183. What is the medium of communication with a computer where programs are written in mnemonics? A. Assembly language B. High level language C. Machine language D. Low-level language

ANSWER: C 184. A _________ a program which converts instruction written in a source language into machine code, which can be read and acted upon by the computer. A. Source code B. Assembler C. Application software D. Compiler

ANSWER: B 185. A detailed step by step set of direction telling a computer exactly how to proceed to solve a specific problem or process as specific task. A. Sequence B. Flow chart C. Computer program D. Process

ANSWER: C 186. What is a program that translated English-like word of high-level language into the machine language of a computer? A. Compiler B. Assembler C. Monitor program D. Interpreter

ANSWER: A 187. ___________ is a software that converts a high level language program into machine or assembly language program. A. ALU B. Cross-assembler

C. Compiler D. CPU

ANSWER: C 188. The purpose of the fetch cycle in a computer is to ____________. A. Obtain instruction B. Obtain input data C. Obtain memory data D. Implement a specific operation

ANSWER: A 189. _____________ refers to a program that translates and then immediately executes statements in a high level language. A. Interpreter B. Synchronous C. Interface D. Operating system

ANSWER: A 190. A _____________ is an instruction in a source language that is to be replac

ed by a defined sequence of instructions in the same source language. A. Statement B. Source code C. Mnemonic D. Macro-instruction

ANSWER: D 191. A very high-dense and probably the most versatile integrated circuit used in digital electronics. It is known to function as the central processing unit of most computer applications. A. Microcomputer B. Micro-integrated C. Macro-integrated D. Microprocessor

ANSWER: D 192. The smallest computer in terms of physical size A. Microcomputer B. Minicomputer C. Mainframe D. Host computer

ANSWER: A 193. A logic/digital circuit that generates an output code for every input signal. A. Enhancer B. Compressor C. Encoder D. Decoder

ANSWER: C 194. What code that gives each digit of a decimal number with a corresponding binary equivalent? A. Binary code B. Gray code C. ASCII D. Binary coded decimal

ANSWER: D 195. Which of the code below is considered as minimum-change code? A. Gray code B. ASCII C. BCD D. ARINC

ANSWER: A 196. A 7-bit alphanumeric code that is widely used A. Gray code B. ASCII C. BCD D. ARINC

ANSWER: B 197. The op-code of a computer instruction A. Mnemonic B. Bionic C. Operand D. Program

ANSWER: A

198. An instruction that causes the program to go another task. A. FLIP B. SUB C. JUMP D. MOVE

ANSWER: C 199. An instruction that can move data from memory to the accumulator. A. FETCH B. MOVE C. ACC D. LOAD

ANSWER: D 200. An instruction tat moves data from accumulator to the memory A. FETCH B. MOVE C. STORE D. LOAD

ANSWER: C 201. Part of the instruction cycle where the instruction is moved from memory to the instruction register. A. ACC B. FETCH C. MOVE D. CLI

ANSWER: B 202. An instruction, which means “clear the interrupt mask”. A. ACC B. DEL C. CANCEL D. CLI

ANSWER: D 203. Refers to a condition wherein the result of an arithmetic operation is more negative than the capacity of the output register. A. Error B. Negative infinite C. Overflow D. Underflow

ANSWER: D 204. Refers to a condition wherein the result of an arithmetic operation is more than the capacity of the output register. A. Error B. Infinite C. Overflow D. Underflow

ANSWER: C 205. Machine instructions represented by mnemonics is considered as A. Machine language B. Personal language C. Assembly language D. Coded language

ANSWER: C 206. The first generation language of instruction, and is considered as the most

primitive instruction that can be given to a computer. A. Machine language B. Assembly language C. COBOL D. 4GL

ANSWER: A 207. COBOL, FORTRAN, and ALGOL are examples of A. Machine language B. Assembly language C. High-level language D. 4GL

ANSWER: C 208. An advanced programming language, more advanced than high-level language. A. Machine language B. Assembly language C. High-level language D. 4GL or 4th generation language

ANSWER: D 209. Translator from high-level program to machine instructions A. Assembler B. Converter C. Encoder D. Compiler

ANSWER: D 210. Translates source program to object program A. Assembler B. Converter C. Encoder D. Compiler ANSWER: D 211. Assemble language to machine language translator A. Assembler B. Converter C. Compiler D. Transponder

ANSWER: A 212. A program in a programming language, as written by the programmer. A. Source program B. Object program C. Machine program D. Original program

ANSWER: A 213. A source program can run in computer only after translation into a machine code by a compiler. This machine code is referred as the A. Source program B. Object program C. Interpreter D. Mnemonic

ANSWER: B 214. A program that can read a source program in high-level language, translates, and executes the statement in one operation. A. Mnemonic B. Object program

C. Interpreter D. Assembler

ANSWER: C 215. A sequence of instructions or statements designed to tell the computer how to carry out a particular processing task. A. Software B. Hardware C. Assembler D. Program

ANSWER: D 216. The instructions and data in a computer system is referred to as A. Software B. Hardware C. Program D. CPU

ANSWER: A 217. Refers to digital interface in which data characteristics are individually synchronized and may be sent at a time. A. Half-duplex B. Asynchronous C. Synchronous D. Simplex

ANSWER: B 218. A network facility used to connect individual similar network segments forming a larger extended network is called _________. A. Routers B. Relays C. Repeaters D. Bridges

ANSWER: C 219. What is the circuit that detects bit error in binary characters? A. Decoder B. Parity detector C. Server D. Comparator

ANSWER: B 220. A device that enables users to transmit computer data and fax messages along telephone lines A. Converter B. Facsimile C. Demodulator D. Modem

ANSWER: D 221. What do you call the devices that allow computers to communicate with other computers through telephone lines or radio frequency? A. Modems B. Disk C. Mouse D. Super computers

ANSWER: A 222. What network facility used to interconnect distinct networks physically? A. Relays

B. Routers C. Repeaters D. Bridges

ANSWER: D 223. Files in E-mail communication are send thru ____________. A. Disk B. Mailbox C. Wires D. Attachment

ANSWER: D 224. The first recipient in E-mail communication. A. Host B. Mail box C. Computer D. Disk

ANSWER: A 225. The interconnections of computers, terminals, and other equipment. A. Cluster B. Network C. Cascading D. Bonding

ANSWER: B 226. A network classification that is usually built and owned by a single company or governmental organization. A. Private data network B. Public data network C. Switched network D. Node

ANSWER: A 227. A network that is built and owned by a common carrier. A. Public data network B. Private data network C. Leased line network D. Node

ANSWER: A 228. Network configuration that let computers share their resources. A. Peer-to-peer network B. Hierarchical network C. Permanent virtual circuit D. Local Area Network

ANSWER: A 229. A computer network configuration that makes the host computer manages a network of dependent terminals. A. Hierarchical network B. Peer-to-peer network C. Local Area Network D. Wide Area Network

ANSWER: A 230. A network switching that creates a dedicated temporary connection between computers in a network. A. Circuit switching B. Message switching

C. Packet switching D. Virtual switching

ANSWER: A 231. The component that provides control or supporting services for other computers, terminals, or devices in a network. A. Host B. Communications controller C. Cluster controller D. Interface equipment

ANSWER: A 232. It is a type of computer networking technology that is used to connect computers that are located within the same room, building, or complex. A. Internet B. Intranet C. Local area network D. Wide area network

ANSWER: C 233. It is a fast computer with a large amount of secondary storage, to which all of the other computers in a network have access for data storage and retrieval. A. Mainframe B. Maincomputer C. File server D. Workstation

ANSWER: C 234. It is also known as cooperative processing that involve using two or more networked computers to perform an application task. A. Client computing B. Server computing C. Distributed processing D. Client/server computing

ANSWER: D 235. A type of server that allows multiple users to take advantage of a single printing device. A. Printer server B. Client server C. Network server D. File server

ANSWER: A 236. This topology is the most efficient centralized network for a small company A. Bus B. Ring C. Tree D. Star

ANSWER: D 237. It is the other term that is used to refer to a central device into which each node of a star network is directly connected. A. Hub B. Central pointer C. Router D. Repeater

ANSWER: A 238. It is simply the term that is used to refer to an I/O device that relies entirely on the host computer for processing. A. Keyboard B. Terminal C. Monitor D. Mouse

ANSWER: B 239. Workstations in a star network that can operate without storage devices. A. Diskless B. Wireless C. Disked D. Wired

ANSWER: A 240. A ___________ network requires that message travel around the ring to nthe desired destination. A. Star B. Bus C. Tree D. Ring

ANSWER: D 241. Networks that transmit data across town using electromagnetic signals are called ____________. A. LANs B. WANs C. MANs D. All of the above

ANSWER: C 242. The process of choosing a terminal on a network to receive data is called _______. A. Polling B. Selection C. Contention D. Option

ANSWER: B 243. A microcomputer attached to a network requires a __________. A. Dongle B. Network interface card C. RS-232 D. Software

ANSWER: B 244. To ___________ is to send a file to a remote computer A. Upload B. Download C. Call D. Transmit

ANSWER: A 245. To ___________ is to receive a file from a remote computer. A. Upload B. Download C. Call D. Transmit

ANSWER: B 246. It is term that is used to describe the conventions of how network components communicate with each other. A. Network model B. Network layer C. Network topology D. Network protocol

ANSWER: D 247. It is term that is used to describe the form or the shape of a network. A. Network model B. Network layer C. Network topology D. Network protocol

ANSWER: C 248. __________ is the process of asking each remote terminal, one at a time, if it has data to send. A. Polling B. Selection C. Contention D. Option

ANSWER: A 249. __________ network topology has more than one level of host computer. A. Star B. Bus C. Hierarchical D. Ring

ANSWER: C 250. It describes its System Services Control Point (SSCP), Logical Units (LU), and Physical Units (PU) as network addressable units. A. Internetworking B. Digital network architecture C. Open system interconnection D. Systems network architecture

ANSWER: D 251. Networks that include telecommunications are called __________. A. LANs B. WANs C. MANs D. All of the above

ANSWER: B 252. A multi-network IBM token ring network is also a __________ network. A. Star B. Bus C. Tree D. Mesh

ANSWER: A 253. Network topology, where stations are connected to a concentric ring through a ring interface unit (RIU). A. Bus B. Mesh C. Token Ring D. Tree

ANSWER: C 254. A _________ will decide which route the message or messages should follow through the network. A. Router B. Bridge C. Repeater D. Gateway

ANSWER: A 255. Used in connecting networks at different sites. A. Router B. bridge C. repeater D. gateway

ANSWER: B 256. Similar to a bridge, which connects networks at different sites, it connects networks with different protocols. A. Router B. Bridge C. GatewayD. Repeater

ANSWER: C 257. Used to extend the length of a network or to expand the network. A. Router B. Bridge C. Gateway D. Repeater ANSWER: D