Virtual (Prioritize!) (PERC DC)
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Transcript of Virtual (Prioritize!) (PERC DC)
ELECTRICITY/MAGNETISM/ELE
CTRICAL CIRCUITS/
SEMICONDUCTORS
1. Two point charge 10 cm apart
produces a force of 1 x 10^-3 g. If
the charges are of equal
magnitude, what is the charge in
statcoulomb?
9.899 statcoulomb
2. Usually, the charge magnitude of
a test-charge is equal to
q (the charge of electron)
3. Who was the first to introduce the
concept of filed lines?
Michael Faraday
4. When a charge distribution is
symmetric, often we use _____ to
simplify electric field calculations.
Gauss’ Law
5. Determine the magnitude of the
electric field inside a sphere that
encloses a net charge of 2 C.
0 (zero)
6. What is the total electric flux
through the surface of a closed
sphere enclosing a net charge of
2 C?
2.26 x 105 NC-1m
2
7. The potential gradient at a
particular point is numerically
equal to _____ at the point.
Electric intensity
8. To get a higher value of
capacitance in a capacitor the
dielectric must be constructed as
thin as possible
9. What is the reciprocal of
capacitance?
Elastance
10. What is the unit of elastance?
Daraf
11. Law which shows that the force
of attraction or repulsion between
two magnetic poles is inversely
proportional to the square of the
distance between them.
Coulomb’s second law
12. When a magnetic substance is
placed near a magnet it will
become a magnet also, this
phenomenon is known as
magnetic induction
13. The capacity of a substance to
become magnetized, and
expressed as the ratio between
the magnetization produced in a
substance to the magnetizing
force producing it.
Magnetic susceptibility
14. The voltage induced in a
conductor is directly proportional
to the rate of change of flux being
cut.
Faraday’s second law of
electromagnetic induction
15. The voltage or emf induced when
the magnetic field is moving or
changing and a conductor is
stationary.
Statically induced emf
16. Reluctance is analogous to
resistance in electrical circuits
and has a unit of At/Wb, its
reciprocal is
Permeance
17. What magnetic materials that can
be easily magnetized in both
directions? Soft magnetic
materials
18. At what temperature does a
magnetic material loses its
ferromagnetic properties?
Curie temperature
19. According to _____, the algebraic
sum of the rises and drops of the
mmf around a closed loop of a
manetic circuit is equal to zero.
Ampere’s circuital law
20. Gaussmeter measures flux
density using what principle?
Hall effect
21. An electromagnetic switch
consisting of a multiturn coil
wound on a iron core and an
armature.
Electromechanical relay
22. What do you call of an
electromagnet with its core in the
form of a close magnetic ring?
Toroid
23. An electrical device has a
resistance of 10 and is supplied
with a 5 ampere constance
current source. If the device is
rated 100 Vdc, determine its
power consumed.
250 W
24. The power dissipated by a 10
load resistor with a current rating
of 5 amperes is _____ if supplied
with a 20 volt dc potential.
40 W
25. How do you connect cells to form
a battery useful for high-power
applications?
In series-parallel
26. In a mesh, the algebraic sum of
all voltages and voltage drops is
equal to zero.
Kirchhoff’s second law
27. The sum of all currents entering a
junction is equal to the sum of
currents leaving away from the
junctions.
Kirchhoff’s first law
28. If a copper wire has an inferred
absolute zero of -234.5 /Co,
determine its temperature
coefficient of resistance at 25
/oC?
0.00385 /oC
29. A certain Thevenin equivalent
circuit has parameters RTH = 10
and VTH = 20V. If this is
converted to Norton’s equivalent
circuit, RN and IN would be
10 and 2A
30. RN and IN of a Norton’s
equivalent circuit are known to be
100 and 10A, respectively. If a
400 load is connected, it will
have a load current of
2 A
31. A chosen closed path of current
flow in a network. In making this
current path there should be no
node nor elements that are
passed more than once.
Mesh
32. A set of circuit elements that
forms a closed path in a network
over which signal can circulate.
Loop
33. In a network. What do we call a
reference point chosen such that
more branches in a circuit met.
Node
34. A common connection between
circuit elements or conductors
from different branches.
Junction
35. A secondary cell whose active
positive plate consists of nickel
hydroxide, and active negative
plate material is powered iron
oxide mixed with cadmium. Its
typical out-put when fully charged
is VO = 1.2V.
Edison cell
36. The maximum current a cell can
deliver through a 0.01 ohm load
during testing.
Flash current
37. In batteries, the material used to
insulate the positive plates from
negative plates are technically
called
Separator
38. Three resistors, R1 = 60 , R2 =
80 and R3 = 100 are
connected in delta. If the network
is to be transformed into star
what would be the value of the
resistor opposite R2?
25.0
39. When can an ac-voltage,
𝑣 = 240 sin 120𝜋𝑡 reach its first
peak?
240 ms
40. The time taken by an alternating
voltage, 𝑣 = 100 sin 120𝜋𝑡 to
reach 20V for the first time
15.3 ms
41. What is the frequency of an
alternating current, if it reaches
45 degrees within 120ms?
60 Hz
42. What is the average voltage of an
alternating voltage, 𝑣 =
100 sin 120𝜋𝑡?
70.71 V
43. What will be the current equation
in a series RC network if supplied
with 𝑣 = 𝑉𝑚𝑠 sin 120𝜋𝑡 source.
The circuit has a power factor pf
= 0.5? 𝒊 = 𝑰𝒎𝒂𝒙 𝐬𝐢𝐧 𝟏𝟐𝟎𝝅 + 𝟔𝟎
44. The power factor (pf) of a series
LC circuit is
0
45. What will happen when the power
factor of a circuit is increased?
Active power increases
46. The apparent power of a series
RC network is given to be 4000
W. If R = 6 , and XC = 8 ,
calculate the true power of the
network.
2400 W
47. What is the significance of
connecting loads in parallel?
It allows independent
operations of loads
48. If a circuit has an admittance of Y
= 0.2 + j0.6, the circuit is
Capacitive
49. The circuit admittance is Y = 0.2
– j0.6, the circuit is
Inductive
50. What will happen to a parallel ac-
circuit if its line frequency is more
than the resonant frequency?
Becomes capacitive
51. If the line frequency of a parallel
ac-circuit is less than the
resonant frequency, the circuit
behaves as
Reactive
52. Absolutely, when can we say that
the circuit is at resonance?
When the voltage and current
are in-phase
53. Inventor of kaleidoscope, a
Scottish physicist who says that
for any dielectric reflector, the
relationship in which the
refractive index is equal to the
tangent of the polarizing angle.
Brewster, Sir David
54. He invented the light-controlled
valve which allowed lighthouses
to operate automatically and won
him the 1912 Nobel prize in
Physics, Who was this Swedish
industrial engineer?
Dalen, Nils
55. British chemist who invented the
electrical primary cell.
Daniell, John Frederic
56. An English obstetrician who
introduced ultrasound scanning.
He pioneered its use as a means
of scanning the growing fetus
without exposure to x-rays.
Donald, Ian
57. He investigated heat and light,
discovered eddy currents induced
in a copper disc moving in a
magnetic field, invented a
polarizer, and made improvement
in the electric arc. Who was this
French physicist who invented
gyroscope?
Foucault, Jean Bernard Leon
58. The people responsible for the
development of the practical
transformers.
Lucien Gaulard & John Gibbs
59. A German scientist who helped
prove the law of conservation of
energy, invented the
opthalmoscope, constructed a
generalized form of
electrodynamics, and foresaw the
atomic structure of electricity.
Helmholtz, Hermann Ludwig
Ferdinand von
60. Who was this US physicist who
invented the cyclotron which
pioneered the production of
artificial radioisotopes?
Lawrence, Ernest
61. A German physicist who
investigated the photoelectric
effect (light causes metals to emit
electrons) and cathode rays (the
stream of electrodes emitted from
the cathode in a vacuum tube).
Lenard, Phillip
62. British physicist who studied the
emission of electricity from hot
bodies, giving the name
“thermionics” of the subject.
Richardson, Owen
63. An English physicist and chemist
who pioneered research into the
radioactive decay of atoms and
coined the term isotope.
Soddy, Frederick
64. A Japanese physicist who
discovered the subatomic
particles called the meson in
1935.
Yukawa, Hideki
65. Elements that has four valence
electrons are classified as
elemental semiconductor
66. The atomic number of an element
represents the number of
protons or electrons
67. The type of crystal lattice in
silicon and germanium.
Face centered cubic (fcc)
68. What is the total charge at the
nucleus of silicon atom?
14e C
69. Which of the following element
configuration that resembles an
alkali metal?
Filled-shell-plus-one-electron
70. Energy required by a valence
electron before it can move or
transfer towards the conduction
band.
Energy gap
71. The energy gap between the
valence band and conduction
band of a semiconductor is in the
order of
one electron volt (1 ev)
72. Typical range of the resistivity of
a semiconductor.
10 – 104 -cm
73. Chemical bond that is significant
in metals.
Metallic bonding
74. What do you call a
semiconductor that is doped with
both donor and acceptor
impurities?
Compensated semiconductor
75. The resistance of a
semiconductor is known as
bulk resistance
76. Silicon is widely used over
germanium due to its several
advantages, what do you think is
its most significant advantage?
Low leakage current
77. Current flow in a semiconductor
that is due to the applied electric
field.
Drift current
78. The movement of charge carriers
in a semiconductor even without
the application of electric
potential.
Diffusion current
79. Typically, how much energy is
required for a valence electron to
move to the conduction band for
a doped semiconductor?
0.05 eV
80. In energy band diagram of a
doped semiconductor, the donor
level
is near the conduction band
81. The acceptor level in a doped
semiconductor
is near the valence band level
82. What is used in the study of the
behavior of free electrons in a
conducting material?
Fermi-Dirac
83. In statistical mechanics, what
distribution function is best used
in analyzing photons?
Bose-Einstein
84. In quantum statistics, the most
suitable functions to be used in
the molecular analysis of gas is
Maxwell-Boltzmann
85. What do you call the boundary
between the energy filled level
and empty level in a
semiconductor material?
Fermi level
86. Which energy level that has free
electrons?
Below the Fermi level
87. The potential required to remove
a valence electron.
Ionization potential
88. A semiconductor that is classified
as a metalloid or semimetal.
Germanium (Ge)
89. Which statement is not true?
Silicon has an oxidation state
of negative four (-4)
90. Compound semiconductors are
also known as
inter-metallic semiconductors
91. What semiconductor that is
mostly used in devices requiring
the emission absorption of lights?
Compound semiconductor
92. For high-speed integrated circuit,
which semiconductor material
given is best to be used?
Gallium arsenide
93. How much impurity concentration
is needed for a sample of silicon
to change its electrical property
from a poor conductor to a good
conductor?
One part per million
94. The restriction of certain discrete
energy levels in a semiconductor
material can be predicted
generally by using what model?
Bohr model
95. At room temperature, in a perfect
silicon crystal, the equilibrium
concentration of thermally
generated electrons in the
conduction band is about
1.5 x 1010
per cubic cm.
96. What is the basis in operations of
semiconductor photoconductors?
EHP optical generation
97. A silicon sample at equilibrium
has a electron concentration of
1.5 x 1010 /cm3, and is doped
with 1015 donors/cm3. Calculate
the minority-carrier
concentrations.
2.25 x 105/cm3
98. Impurities with energy level or
states close to the band edges
are called
shallow states.
99. When an impurity used in doping
produces a level or state that is
close to the center of the gap, it is
called _____ impurity.
Deep state
100. The mobility of electrons and
holes in a semiconductor are
affected mainly by what
scattering mechanisms?
Impurity and lattice scattering
101. In semiconductors, what
scattering mechanism that has a
the smallest effect?
Crystal imperfection scattering
102. Calculate the total carrier mobility
in a semiconductor if the impurity
scattering L = 0.3 m2/vs.
0.14 m2/vs
103. Semiconductor that has the
highest heat conductivity and
therefore used as a heat sink.
Diamond
104. The semiconductor that is used in
xerography.
Selenium (Se)
105. What semiconductor that is good
for high-temperature
applications?
Silicon carbide (SiC)
106. Among the given semiconductors
below, which has the highest
mobility?
Indium antimonide
107. For an electroluminescent of
green and red lights, which
semiconductor is best?
Gallium phosphide
108. A semiconductor glass is known
as
amorphous semiconductor
109. Typical range of power
dissipation for a semiconductor
be considered as “low power” or
“small signal”.
Less than 1 watt
110. 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
be 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?
Zinc Sulfide (Zns)
111. Which of the following
semiconductors has the smallest
energy gap?
InSb
112. The ease with which a charge
carrier (electron or hole) moves in
a semiconductor material is
known as mobility. It is
InSb
113. In semiconductor materials,
electrons have a higher value of
mobility than holes, but which
semiconductor material has the
slowest electron-mobility?
AlP
114. What is the average lattice
constant of most semiconductors
materials?
0.5 nm
115. What is formed when an n-type
and p-type semiconductors are
brought together?
Pn junction
ELECTRONICS CIRCUITS
(DIODES & TRANSISTORS)
1. When the diode is supplied with a
forward direction potential 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 known as
Ans. cut-off current
2. As the operating temperature of a
reverse-biased diode is
increased, its leakage of reverse
saturation current will
Ans. increase exponentially
3. Calculate the new threshold
voltage of a germanium diode
when it operates at 100 ˚C.
Ans. 0.113 V
4. 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?
Ans. 1.66 µA
5. In every increase of 10 ˚C in the
operating temperature of a diode
will cause its reverse saturation
current to
Ans. double
6. The resistance of the diode that
is significant when operating with
a small ac signal.
Ans. dynamic resistance
7. When a diode is used in large ac
voltages, the resistance that is to
be considered is
Ans. average resistance
8. At forward bias condition, what
will happen to the diode
resistance when the applied
voltage is increased?
Ans. will decrease
9. 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?
Ans. transition capacitance
10. 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 called
Ans. diode capacitance
11. What capacitance is significant
when the diode is forward
biased?
Ans. diffusion capacitance
12. The time taken by the diode to
operate in the reverse condition
from forward conduction.
Ans. reverse recovery time
13. In operating a diode at high-
speed switching circuits, one of
the most important parameters to
be considered is
Ans. reverse recovery time
14. The time required for forward
voltage or current to reach a
specified value after switching the
diode from its reverse-to-forward-
biased state.
Ans. forward recovery time
15. A certain diode has a maximum
power dissipation of 500 mW at
room temperature and a liner
power derating factor of 5.0
mW/˚C. How much power the
diode can handle if operate4d at
50˚C?
Ans. 375 mW
16. Diode whose negative resistance
depends on a specific form of
quantum-mechanical bond
structure of the material.
Ans. Gunn diode
17. 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.
Ans. backward diode
18. 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.
Ans. thyrector
19. A type of Reade diode that uses
a heavily doped n-typed material
as its drift region.
Ans. IMPATT diode
20. A device containing more than
one diode. An example is the
full-wave bridge-rectifier
integrated circuit.
Ans. diode pack
21. Is the combination of the
inductance of the leads and
electrodes capacitance of the
junction and the resistance f the
junction of a semiconductor diode
Ans. diode impedance
22. The appearance of RF current
oscillations in a dc-biased slab of
n-type gallium arsenide in a 3.3
kV electric field.
Ans. Gunn effect
23. The device that is formed when
an n-type and p-type
semiconductors are brought
together.
Ans. junction diode
24. When the diode is supplied with a
forward direction potential 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 of pass. This very small
current is known as
Ans. cut-off current
25. As the operating temperature of a
reverse-biased diode is
increased, its leakage or reverse
saturation current will
Ans. increase exponentially
26. Calculate the new threshold
voltage of a germanium diode
when it operates at 100 ˚C.
Ans. 0.113 V
27. 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?
Ans. 1.66 µA
28. In every increase of 10 ˚C in the
operating temperature of a diode
will cause its reverse saturation
current to
Ans. double
29. The resistance of the diode that
is significant when operating a
small ac signal.
Ans. dynamic resistance
30. When a diode is used in large ac
voltages, the resistance that is to
be considered is
Ans. average resistance
31. At forward bias condition, what
will happen to the diode
resistance when the applied
voltage is increased?
Ans. will decrease
32. 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?
Ans. transition capacitance
33. 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 called
Ans. diode capacitance
34. What capacitance is significant
when the diode is forward
biased?
Ans. diffusion capacitance
35. The time taken by the diode to
operate in the reverse condition
from forward conduction.
Ans. reverse recovery time
36. In operating a diode at high-
speed switching circuits, one of
the most important parameters to
be considered is
Ans. reverse recovery time
37. The time required for forward
voltage or current to reach a
specified value after switching the
diode from its reverse-to-forward-
biased state.
Ans. forward recovery time
38. 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?
Ans. 375 mW
39. Diode whose negative resistance
depends on a specific form of
quantum-mechanical bond
structure of the material.
Ans. Gunn diode
40. 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/
Ans. backward diode
41. 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.
Ans. thyrector
42. A type of Read diode that uses a
heavily doped n-type material as
its drift region.
Ans. IMPATT diode
43. A device containing more than
one diode. An example is the
full-wave bridge-rectifier
integrated circuit.
Ans. diode pack
44. It 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.
Ans. diode impedance
45. The appearance of RF current
oscillations in a dc-biased slab of
n-type gallium arsenide in a 3.3
kV electric field.
Ans. Gunn effect
46. 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.
Ans. alloy-diffused transistor
47. In a semiconductor device, a p-n
junction formed by alloying a
suitable material such as indium
with the semiconductor.
Ans. alloy junction
48. A transistor in which one or both
electrodes are created by
diffusion.
Ans. diffused transistor
49. A diffused transistor in which the
base, emitter, and collector
electrodes are exposed at the
face of the wafer which is
passivated (has an oxide layer
grown on it) to prevent leakage
between surface electrodes.
Ans. diffused planar transistor
50. A bipolar transistor in which the
base region has been diffused in
the semiconductor wafer.
Ans. diffused-base transistor
51. When n and p materials are both
diffused into the semiconductor
wafer to provide emitter and base
junctions, the transistor is called
Ans. diffused-emitter and base
transistor
52. A mesa transistor whose base is
an n-type layer diffused into a p-
type wafer, the p-type wafer
serves as the collector. Its
emitter is a small p-type area
diffused into or alloyed with the n-
layer.
Ans. diffused-mesa transistor
53. A transistor in which the
semiconductor wafer is etched
down in steps so the base and
emitter regions appear as
physical plateaus above the
collector region.
Ans. mesa transistor
54. An alloy-junction bipolar RF
transistor for which the impurity
concentration is graded from high
on the emitter side of the base
wafer to low on the collector side.
This creates an internal drift field
which accelerates current carriers
and raises the upper frequency
limit of the transistor.
Ans. drift-field transistor
55. A transistor in which a thin metal
crystal is overlaid on another
mesa crystal.
Ans. double-diffused epitaxial
mesa transistor
56. In diffused transistors, what do
you call a figure expressing the
ability of material carriers to
diffuse?
Ans. diffusion constant
57. A BJT that is made by first
growing the emitter and collector
regions as a crystal into which
the base region is later diffused
while the crystal is being pulled.
Ans. grown-diffused transistor
58. A junction transistor made by
adding different impurities
successively to a crystal in its
molten state, and then slicing the
resulting npn formations from the
finished crystal.
Ans. grown-junction transistor
59. A transistor having tiny emitter
and collector electrodes that are
formed by alloying a thin film of
impurity material with a collector
and emitter pits facing each other
on opposite surfaces of the
semiconductor wafer
Ans. microalloy transistor
(MAT)
60. A microalloy transistor having a
uniform base region that is
diffused into the wafer before the
emitter and collector electrodes
are produced by alloying
Ans. microalloy-diffused
transistor
61. The process of growing thin oxide
film on the surface of a planar
semiconductor device to protect
the exposed junction(s) from
contamination and shorts.
Ans. passivation
62. A planar epitaxial transistor which
has been passivated to protect
the exposed junctions.
Ans. planar epitaxial
passivated transistor
63. A transistor in which the emitter,
base and collector elements
terminate on the same plane of
the silicon wafer.
Ans. planar transistor
64. Usually, a pnp transistor is made
by means of electrolysis and
electroplating. The emitter and
collector are formed on opposite
sides of a semiconductor wafer
by training two jets of electrolyte
against its opposite surfaces to
etch and then electroplate the
surfaces.
Ans. surface-barrier transistor
65. If the base-emitter junction is
reversed biased and the base-
collector junction is forward
biased, the transistor will be at
what region of operation?
Ans. cut-off region
66. A transistor with β=100 is
connected as common base, was
found to have a leakage current
ICBO = 1 µA. If the said
transistor is configured as
common emitter, what is the
approximate value of its ICEO?
Ans. 100 µA
67. How is the collector cut-off or
reverse saturation current ICBO
related to the emitter cut-off
current IEBO?
Ans. ICBO ≈ IEBO
68. A transistor is said to be
configured as common emitter if
the emitter terminal is
Ans. not used as an input nor
output
69. Hybrid parameter that is usually
neglected in most circuit analysis.
Ans. hr and ho
70. In most transistor input equivalent
circuit it comprises of a resistor
and a
Ans. voltage source
71. The graph of the product of
collector-emitter voltage VCE and
collector current IC in the
transistor output characteristic
curve
Ans. maximum power curve
72. What will happen to the channel
of a JFET as current flows to it?
Ans. skews
73. The voltage across the gate-
source terminal of a FET that
causes drain current ID equals to
zero.
Ans. pinch-off voltage
74. An early version of the field effect
transistor in which limited control
of current carriers near the
surface of a semiconductor bar or
film was obtained by an external
field applied transversely.
Ans. fieldistor
75. What is the insulator used in
most MOS-FET?
Ans. SiO2
76. 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.
Ans. 2.5 mA
77. 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?
Ans. zero
78. In MOSFET, it is the foundation
upon which the device will be
constructed and is formed from a
silicon base
Ans. substrate
79. The amount of voltage needed at
the gate-source terminal for an
enhancement type MOSFET so
that a channel can be formed for
the current to flow.
Ans. threshold voltage
80. To switch off the depletion type
MOSFER, the channel should be
depleted. Depletion of the
channel is done by applying
enough voltage across the gate-
source terminal. What do you call
this voltage?
Ans. pinch-off voltage
81. In an n-channel enhancement
type MOSFET, the gate voltage
should be ______ with respect to
the source in order to produce or
enhance a channel.
Ans. positive
82. To deplete a channel from a p-
channel IGFET depletion type,
the gate voltage should be
______ with respect to the
source terminal.
Ans. positive
83. 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.
Ans. 5.0 mS
84. An n-channel MOSFET depletion
type has a drain saturation
current IDSS = 10 mA and a
pinch-off voltage of -4 V.
Calculate the maximum
transconductance of the
transistor.
Ans. 5.0 mS
85. 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.
Ans. 2.4 mS
86. What will happen to the
conductivity of the channel of an
enhancement type MOSFER if
the proper gate voltage is
increased?
Ans. decreases
87. The cutoff frequency of a JFET is
dependent on channel length by
a factor of
Ans. 1/L2
88. An n-channel enhancement type
MOSFET has a threshold voltage
of VT = 2.5 V. If the applied gate-
source voltage VGS = 4 V, what
is the approximate drain current
ID?
Ans. 0.675 mA
89. Which FET has a wide and short
effective channel?
Ans. V-MOSFET
90. The load line position is
dependent of
Ans. the load resistance and
the supply voltage
91. What will happen to the
magnitude of the load line slope if
the load resistance is increased?
Ans. decreases
92. One method of stabilizing
transistor circuits is to add an
emitter resistance. This
resistance causes the load line
slope to
Ans. become less negative
93. The power gain that is lost due to
the emitter bias resistor can be
recovered by
Ans. shunting a by-pass
capacitor
94. When a capacitor is involved at
the output circuit of a transistor
amplifier it would mean
Ans. a different dc and ac load
line
95. How does the emitter by-pass
capacitor affect the dc load line?
Ans. it does not affect the dc
load line
96. In analyzing the quiescent
currents and voltages, on what
load line do you refer?
Ans. dc load line
97. The position of the Q-point along
the load line is greatly affected by
what component?
Ans. base-resistor
98. What will happen to the position
of the Q-point if the resistance
base-resistor is increased?
Ans. it moves downward
99. For a fixed-biased transistor
circuit, what will happen to the Q-
point when the operation
temperature rises?
Ans. it moves upward
100. For a battery operated transistor
circuit, where is a good position of
the Q-point in order to minimize
battery consumption?
Ans. near cutoff region
101. When troubleshooting a typical
transistor amplifier in the active
region, VCE is usually _____ the
supply voltage VCC.
Ans. about 25% to 75% of
102. Calculate the stability factor due to
the variation of ICBO from 1 nA to
21 nA when the temperature
changes from room temperature to
100 ˚C. The change in collector-
current due to the change of ICBO
was found to be 0.5 µA.
Ans. 25
103. The higher the stability factor
means, a transistor circuit that is
more sensitive to temperature
Ans. variations, and therefore
undesired
104. What stability factor that gives the
highest value for a typical voltage-
divider bias transistor circuit?
Ans. S (ICO)
105. Calculate the change in the
collector current due to the change
in ICO for a transistor circuit at 100
˚C. ICO at room temperature is
given to be 0.1 nA and increases to
20 nA at 100 ˚C. The circuit has a
stability factor S(ICO) = 25.
Ans. 0.5 µA
106. For most common-emitter
configuration with different methods
of biasing, what is the maximum
stability factor due to the change of
the reverse saturation current ICO?
Ans. β + 1
107. What is the approximate output
impedance of a common-emitter
fixed-bias configuration? The
collector resistance RC is the only
load resistance/
Ans. RC
108. A FET is biased with a voltage-
divider configuration and is set at
the active region. Ideally, what is
the gate current?
Ans. 0 mA
109. What type of FET that can be
biased with both negative and
positive gate-source voltage VGS?
Ans. MOSFET depletion type
110. How do you classify an amplifier
used to amplify either amplitude
modulated (AM) or frequency
modulated (FM) signals?
Ans. class S
111. Which class of amplifiers that have
the highest efficiency?
Ans. class D
112. Transistorized class C power
amplifiers will usually have an
efficiency of
Ans. 33%
113. For pulse-amplification, class D
amplifier is mostly used. How
efficient is a class D amplifier?
Ans. its efficiency reaches over
90%
114. The Q-point of a class D amplifier
can be set or positioned at what
region in the load line?
Ans. any of these
115. What do you call an amplifier that is
biased to class C but modulates
over the same portion of the curve
as if it were biased to class B?
Ans. class BC
116. 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 by
a transformer to the load.
Ans. transformer-coupled push-
pull amplifier
117. A push-pull amplifier that uses npn
and pnp transistors to amplify the
positive and negative cycles
respectively.
Ans. complementary-symmetry
amplifier
118. A push-pull amplifier that uses
either npn or pnp as its final stage.
The circuit configuration looks like
the complementary-symmetry.
Ans. quasi-complementary push-
pull amplifier
119. Distortion that is due to the inability
of an amplifier to amplify equally
well all the frequencies present at
the input signal/
Ans. amplitude distortion
120. Calculate the second harmonic
distortion for an output signal
having a fundamental amplitude of
3 V and a second harmonic
amplitude of 0.3 V.
Ans. 10 %
121. An amplifier has the following
percent harmonic distortions: D2 =
10%, D3 = 5% and D4 = 1%. What
is the amplifier %THD?
Ans. 11.22%
122. T-equivalent circuit for transistor is
considered as a _____
representation/
Ans. physical
123. What transistor model that uses a
parameter value that is directly
derived from the operating
condition?
Ans. re or dynamic model
124. The transistor model that is best
suited for high frequency
applications/
Ans. Giacolleto model
125. Another name of Giacolleto model
for transistor modeling is
Ans. hybrid-pi model
126. What model is appropriate to use, if
for a given transistor amplifier, beta
(β) is the only parameter available
and we want to solve for its input
and output impedances?
Ans. dynamic model
127. When the transistor is operating at
saturation region, dc-current is best
determined by using what model?
Ans. Ebers-Moll model
128. 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 or last
stage.
Ans. cascode configuration
129. Famous transistor amplifier
configuration designed to eliminate
the so called Miller effect.
Ans. cascode amplifier
130. Transistor arrangement that
operates like a darlington but uses
a combination of pnp and npn
transistors instead of both npn.
Ans. feedback pair
OP AMPS/ COMPUTERS
1. Thin-film integrated circuit refers
to film thickness of
approximately 1um.
2. Classifications of ICs according
to functions include linear, digital
and microwave. Which of these
classes greatly relies on hybrid
technology? Microwave ICs
3. The term “monolithic” is derived
from the Greek words monos and
lithos which respectively mean
single and stone (single stone)
4. Devices or components such as
transistors and diodes are mostly
fabricated in ICs by diffusion
5. In most planar ICs, what do you
call the layer that protects the
surface of the chip from external
contaminants? Oxide layer
6. Which comes first in the planar
process of fabricating ICs?
Crystal growth
7. A technique used for obtaining a
relatively large single crystal from
a semiconductor material. the
process consists essentially of
dipping a tiny seed crystal into a
crucible of molten mass of the
same substance and then slowly
withdrawing it while rotating.
Czochralski method.
8. In IC fabrications, the substrate is
usually produced by Czochralski
process.
9. The process used to grow a layer
of single-crystal semiconductor
as an extension of the existing
crystal wafer of the same
material. epitaxial
10. In fabricating ICs using planar
technology, what is the basic
method of adding impurities?
Diffusion
11. The introduction of impurities into
a semiconductor inside a hot
furnace during IC fabrication.
Diffusion
12. A method of introducing
impurities in IC fabrication
wherein the appropriate ions are
carried by an accelerating beam.
Ion-implantation
13. Which method of doping that is
used in producing narrow regions
in an IC? Ion-implantation
14. Type of diffusion in which the
impurity concentration at the
semiconductor surface is
maintained at a constant level
throughout the diffusion cycle.
Constant-source diffusion
15. An alternative method rather than
diffusion in introducing impurities
into a semiconductor wherein the
impurities are made to penetrate
into the wafer by an ion beam.
Ion-implantation.
16. A method of producing integrated
circuit by photographing a pattern
of the circuit on a suitable light-
sensitized surface of semicon-
ductor and chemically etching
away unwanted portions of the
surface. Photolithographic
process.
17. In IC fabrication, the photo-
sensitive emulsion coated at the
wafer surface to be masked is
called photoresist
18. The removal of unmasked Silicon
Dioxide (SiO2)at the wafer
surface in IC fabrication etching
19. The removal of the remaining
photoresist in the wafer after
etching during IC fabrication.
Stripping.
20. Covering or coating on a
semiconductor surface to provide
a masked area for selective
etching or deposition masking
21. In most IC fabrications, how is
the connection pattern between
components defined? By
masking
22. What do you call the process of
interconnecting the components
in an IC during fabrication?
Metallization
23. The conducting material that is
mostly used to interconnect
components on chips during
metallization process. Aluminum
24. Is the process of making the
semiconductor chip or wafer
insensitive to any contaminations
that might cause drift of
parameter or premature failure.
Passivation
25. Passivation of semiconductor
wafer by forming a layer of an
insulating oxide on the surface
oxide passivation
26. In monolithic ICs, electrical
isolation between devices on the
same substrate is achieved by
fabricating them in an electrically
isolated region known as
isolation pockets or tubs.
27. Which of the isolation techniques
in IC fabrication that is commonly
used? Junction isolation
28. Isolation of devices in integrated
circuit by forming a silicon oxide
layer around each devices is
known as oxide insulation, and
this is a good example of
dielectric isolation
29. An operational amplifier must
have at least how many usable
terminals? 14 terminals
30. What type of amplifier commonly
used at the output stage of op-
amps? Complementary
amplifier
31. the transistor configuration used
at the output complementary
stage of most op-amps common-
collector
32. the stage followed by the output
complementary in op-amps
functional block diagram level
shifter
33. what is the purpose of a level
shifter in op-amps? To set
and/or adjust the output
voltage to zero when input
signal is zero.
34. Primarily, op-amps are operated
with bipolar power supply,
however, we can also use single
polarity power supply by
generating a reference voltage
to ground.
35. Calculate the CMRR of an op-
amp having a common-mode
gain of 10 and a differential-mode
gain of 100,000. 80
36. The non-inverting and inverting
inputs of an op-amp have an
input voltage of 1.5mV and
1.0mV, respectively. If the op-
amp has a common-mode
voltage gain of 10 and a
differential mode gain of 10000,
what is its output voltage?
5.0125V
37. What is the maximum output
voltage swing of an op-amp?
+Vsat to –Vsat
38. The uA741 op-amp has a CMRR
of 90dB and a differential-mode
gain voltage amplification of
200,000. What is the op-amp’s
common-mode voltage gain?
6.324
39. The current needed at the input
of an op-amp to operate it
normally input bias current
40. 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? Input offset current
41. the change in input offset current
due to temperature change input
offset current drift
42. 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? Input threshold voltage
43. 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
output offset voltage
44. calculate the output offset voltage
of an inverting amplifier using op-
amp with an input offset current
of 10nA. the current is having an
input resistance of 10k-ohm and
a feedback resistance of 100k-
ohm. 1.0mV
45. an op-amp inverting amplifier
uses a feedback resistor of 100k-
ohm and input resistor of 10k-
ohm. If the op-amps input offset
voltage is 2.0mV, approximate
the amplifier output offset voltage
due to this input offset voltage.
22mV
46. the output offset voltage of an op-
amp is due to the input offset
current and voltage. If 1mV is due
to the input offset current and
22mV due to the input offset
voltage, what is the total output
offset voltage of the op-amp?
23mV
47. how will you minimize the output
offset voltage due to the input
offset current of an op-amp? By
installing a bias-current-
compensating resistor
48. the approximate value of the
bias-current compensating
resistor in op-amp circuits is:
equal to the parallel
combination of the input and
feedback resistors
49. in op-amp analysis, the input
offset voltage is represented by a
battery
50. what is the effect of the input
offset voltage to the output
voltage if the op-amp has no
feedback element? Causes the
output to saturate either towards
positive or negative.
51. How can we minimize the effect
of the input offset current and
input offset voltage at the output
offset voltage? By making the
feedback resistance small
52. An op-amp is wired as an
inverting amplifier with an input
and feedback resistances of 1k-
ohm and 100k-ohm respectively.
When the input signal is set to
zero, the output was found to
have an offset voltage of 101mV.
Calculate the input offset voltage.
1.0mV
53. What is the most effective way of
minimizing the output offset
voltage of an op-amp? By
properly using and adjusting
the offset-null terminals
54. In large signal dc-amplifiers using
op-amp, which parameter has the
least effect on its performance?
Drift
55. For ac-amplifiers using op-amps
what parameters can affect its
performance. Slew rate and
frequency response
56. If an op-amp is used to amplify
small ac-signals, what parameter
should you greatly consider to
ensure better performance?
Frequency response
57. What do we mean by internally
compensated op-amps? op-amps
with internal frequency
compensation capacitor to
prevent oscillation
58. The frequency at which the open-
loop gain of an op-amp is 0.707
times its value at very low
frequency. Break frequency
59. The reduction of op-amps gain
due to increasing operating
frequency. Roll-off
60. Frequency at which the voltage
gain of op-amp reduces to unity.
Unity-gain bandwidth product
61. An op-amp has a specified
transient response rise time of
0.3us, calculate its unity-gain
bandwidth. 1.167MHz
62. What is the maximum signal
frequency that can be used in an
op-amp having a specified slew
rate of 0.5v/usec? The maximum
output voltage desired is 5V.
16kHz.
63. What must be the slew rate of an
op-amp to be used in order to
provide an undistorted output
voltage of 10V at a frequency of
100,000 rad/sec. 1.0V/usec
64. An op-amp zero crossing
detector without hysteresis.
Has no feedback.
65. What is the noise gain of op-
amps? 1+Rf/Ri
66. In most ac-amplifiers using op-
amps, the feedback resistor is
shunted with a very small
capacitance, what is its purpose?
To minimize high-frequency
noise
67. Approximate the noise-gain of an
inverting adder using op-amps if
it has five inputs six(6)
68. What is true about the external
frequency-compensation
capacitor? The lower its value,
the wider its bandwidth.
69. Typical value of the external
frequency-compensating
capacitor of op-amps. 3.0-30 uF
70. The magnitude of the op-amps
input offset voltage before it can
be classified as a low-input offset
voltage op-amp. 0.2mV.
71. Op-amps whose internal
transistor biasing can be
controlled externally are
categorized as programmable-
op-amps
72. The most popular op-amp
packages are the metal can, 8-
pin DIP, and the SMT. Which of
these corresponds to TO-99?
Metal can
73. Dual-in-line or DIL package is
designated as TO-116
74. For high-density ICs, involving
many op-amps, what packaging
is most suitable? SMT
75. 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 a
large ac-winding to change
accordingly. Saturable reactor
76. a saturable reactor with
regenerative feedback. Magnetic
amplifier
77. an electronic switch that has the
highest single-device current
capacity and can withstand
overloads better. ignitrons
78. which power control switching
method that greatly generates
RFI or EMI and is therefore
limited to low-frequency
applications? Phase-control
79. a converter that changes ac-
voltage frequency from one to
another. Cycloconverter
80. in electronic converters,
what signal is mostly
used to trigger the active device?
Square wave
81. which of the trigger diodes has
the highest-holding voltage?
Bidirectional-trigger diac
82. general term of electronic devices
used to control or trigger large-
power switching devices. Break-
over devices
83. a break-over device that is
basically a diode. Trigger diode
84. the voltage decreased across the
Anode (A) and cathode (K) of an
SCR from non-conducting state
to conducting state. Breakback
voltage.
85. An SCR rated 10A is used in the
controlling switch in a circuit
powered by 50 Vdc. When the
SCR fires ON, its Anode (A) to
Cathode (K) voltage was
observed to be 2V. Calculate the
breakback voltage of the SCR.
86. 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? Water
cooling
87. 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? By using a blocking-
equalizing resistor
88. A circuit used for voltage
equalization during ON-OFF
switching action of SCRs in
series. Snubber circuit
89. 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?
Firing delay angle
90. 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? 120 times (FW)
91. a three terminal device that
behaves roughly like SCRs,
except that it can conduct current
in either direction when at ON.
SBS
92. a thyristor that is very similar to
an SCR except that it has a low
voltage and current ratings. It is
very temperature stable, and is
therefore suitable to be used as a
triggering device. SUS
93. silicon unilateral switches (SUS),
generally have a breakover
voltage of 8V, however, this value
can be altered by normally
connecting a zener diode. How is
the diode installed? Diode’s
cathode to SUS’s gate and
diode’s anode to SUS’s
cathode
94. a silicon unilateral switch (SUS)
has a forward breakover voltage
of 8V. 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 3.9V, what is the
new forward breakover voltage of
the device? 4.50V
95. relate the magnitude of the dc-
output voltage to the ac input rms
voltage of a full-wave rectifier.
Vdc=0.90Vrms
96. determine the dc-voltage of a full-
wave bridge rectifier when the
input ac-voltage is 24Vrms. 21.6V
97. ripple factor of a full-wave
rectifier. 0.48
98. A 20V-dc power supply was
found to have a ripple voltage of
2Vrms when supplying 1.5amps
load. Calculate its percent ripple.
10.0%
99. Which power supply filter gives
the smallest ripple voltage?
Multi-section LC-filter
100. Which regulator is the most
inefficient? Shunt
101. Sampling circuit used in most
voltage regulators. Voltage-
divider network
102. a 12Vdc power supply is
regulated using 7805IC and is
used in TTL circuits that require a
0.2 amps current. Determine the
dropout voltage of the system. 7V
103. a load draws 1A current from a
10-V regulated power supply.
Calculate the power dissipated by
the regulator if it has an input
voltage of 16V. 6 watts
104. what three-terminal IC regulator
that has a variable negative
voltage output? 337
105. in a three-terminal adjustable
positive voltage regulator (317),
what is the bandgap voltage
between the output terminal and
adjustment terminal? 1.25V
106. typical ripple rejection of most
three-terminal voltage regulators.
0.1%
107. 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 for
this regulator in order to provide
the required current? By the use
of external pass transistor
108. 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? By installing a
snubber circuit.
109. In switching SCRs to on-state,
the current rises rapidly and
some-times causes damage to
the device. One way of
preventing this to happen is by
connecting an inductance in
series with the load. If for
example, an SCR with a di/dt
rating of 100A/us and is used in
220 Vac, what should be the
value of the inductance to be
used? 2.48uH
110. When SCRs switches to “off”
from on-state, a voltage across
the anode and cathode rises
rapidly, this voltage change
creates a voltage gradient
internally and may cause the
SCR to trigger again. To prevent
this unscheduled firing, a
capacitor may be installed across
the SCR. For an SCR with a
maximum forward-blocking
voltage of VFBM=500V and a
maximum dv/dt of
25V/us,calculate the capacitance
needed to prevent unscheduled
firing if the SCR has a load of 10-
ohm. 2uF
111. One of the major concerns in
power electronics is to clean-up
or shape-up the utility-supply
voltage (the wall outlet
220V/60Hz) from disturbances
such as overvolt, undervolt,
voltage spikes and harmonic
distortions. What circuit is used
for this? Power conditioners
112. 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 map-entered
variable technique includes
variable into the table.
113. A suitable method in simplifying
Boolean expression when the
system deals with more than six
variables. Quine-mccluskey
tabular method
114. If the fan out of a logic gate is not
enough, a/an buffer should be
used.
115. Is considered as a controller
inverter. XOR
116. Known as universal gates NOR
and NAND
117. The number of NAND-gates
needed to form an OR-gate. 3
118. Flip-flop that changes state every
time the input is triggered.
Master slave flip-flop
119. Type of memory that is formed by
a series of magnetic bubbles at
the substrate bubble memory
120. Digital device similar to that of a
ROM and whose internal
connections of logic arrays can
be programmed by passing high
current through fusable links.
PLA and PAL
121. A circuit used for selecting a
single output from multiple inputs
universal logic module (ULM)
122. 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? Twisted ring counter
123. Refers to the ability of a logic
circuit to withstand noise
superimposed on its input signal.
Noise immunity
124. 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. Fan-in
125. A logic circuit family with a supply
voltage of 25V. and are generally
used in industry where machinery
causes electrical noise and large
power line transients to
occur.HLDTL
126. 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?
It increases the switching
speed
127. PMOS are generally supplied
with a voltage up to 15 V
128. NMOS can be interlaced to
CMOS by providing a pull-up
resistor
129. a digital IC whose output
transistor has no internal pull-up
resistor. Open-collector
configuration
130. in digital ICs, such as buffers and
registers, what output
configuration is used if they are
intended for “busing” ? tri-state
output
131. in TTL ICs, which input
configurations gives a high-input
impedance at both logic states
(HIGH and LOW state)?
Substrate pnp input
132. what is the purpose of internal
clamping diodes at the input of a
logic circuit? To minimize
negative ringing effects
133. in TTL ICs with more than one
gates available, sometimes not
all gates are used. How will you
handle these unused gates?
Force the output to go HIGH
134. how will you handle unused
inputs in a logic gate/logic IC?
Pull them up or down,
depending on circuit function
INSTRUMENTATION/ ENERGY
CONVERSION/ OTHERS
1. An instrument which depends on
current in one or more fixed coils acting on one or more pieces of soft iron, at least one of which is movable.
moving-iron instrument
2. 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 an
adjacent coil or coils carrying current or by two or more current-carrying coils whose axes are displaced by a
fixed angle? moving-magnet instrument
3. What ammeter is mostly used in
measuring high-frequency currents? thermocouple
4. This instrument measures
temperatures by electric means, especially temperatures beyond the range of mercury thermometers.
pyrometer
5. This instrument refers to that one which measures the intensity of the
radiation received from any portion of the sky pyranometer
6. A device used to mechanically measure the output power of a motor. dynamometer
7. An indicating instrument whose movable coils rotate between two stationary coils, usually used as
wattmeter. electrodynamometer
8. Error in ohmmeter reading is due to
battery aging
9. Which of the ammeter below that has no insertion error?
clamp-meter
10. To prevent damage of the multirange ammeter during selection, a/an
_________ should be used. Ayrton shunt
11. Voltage measurement in a high
impedance circuit requires a voltmeter
with high input impedance
12. If a meter with a full-scale current of 100uA is used as an ac voltmeter with half-wave rectification, its ac sensitivity
is 4,500 Ω/V
13. The zero-adjust control in an analog
type ohmmeter is used to compensate for the differing internal battery voltage
14. Dynamometers are mostly used as wattmeter
15. What damping method is generally
used in dynamometers? air friction
16. Which dynamometer instrument has a
uniform scale? wattmeter
17. For a dynamometer to be able to
measure high current, a ___ should be used. current transformer
18. The scale of a hot wire instrument is a/an ________ function. squared
19. Moving iron instruments have a scale function that is squared
20. To increase the measuring capability of a moving-iron ac meter, a ____ should be used.
different number of turns of operating coil
21. Which electrical instruments below is
the most sensitive? PMMC
22. Controlling torque in PMMC.
spring action
23. What damping method is used in induction type ammeters?
electrostatic damping
24. Induction type instruments are mostly used as
watt-hour meter
25. The force(s) that is(are) acting on the pointer of an indicating instrument as
they rest on there final deflected position. (Note: damping torque is 0). controlling & deflecting torques
26. What is (are) the force(s) acting on the pointer of an indicating instrument when it is in motion? controlling, damping, and defecting
torques
27. A Kelvin electrostatic voltmeter uses what method of damping?
fluid friction
28. In a moving coil ammeter, a ________ is connected in series with the coil to
compensate for temperature variations. swamping resistor
29. What is this 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?
vane-type instrument
30. Its 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. Kelvin voltmeter
31. What is that instrument used for
measuring the strength and direction of magnetic fields? magnetometer
32. What do you call of that instrument used for measuring reactive power vars?
either varmeter or reactive volt-ampere meter
33. This is a method of using a
Wheatstone bridge to determine the distance from the test point to a fault in telephone or telegraph line or cable.
Varley loop
34. This refers to a four-arm ac bridge used for measuring inductance against
a standard capacitance. Maxwell bridge
35. Refers to an ac bridge for measuring
the inductance and Q of an inductor in terms of resistance, frequency and a standard capacitance.
Hay bridge
36. 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 resistance bridges. Kelvin double bridge
37. A type of four-arm capacitance bridge in which the unknown capacitance is compared with a standard
capacitance. This bridge is frequently employed testing electrolytic capacitors, to which a dc polarizing
voltage is applied during the
measurement. What is this bridge? Schering bridge
38. What do you call of that frequency-sensitive bridge in which two adjacent arms are resistances and the other
two arms are RC combinations? Wein bridge
39. When the capacitors of a Wein bridge
are replaced by inductors, the bridge becomes Wein inductance bridge
40. 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. slide-wire bridge
41. Electrical machine that converts ac voltage to dc voltage, or vice versa. rotary converter
42. Electrical machine that changes ac voltage at one frequency to another ac voltage at another frequency.
frequency converter
43. A Synchronous type ac-motor, uses a dc – generator to supply dc
– excitation to the rotating field
44. In a compound generator, which field winding usually, has a lower
resistance? series field winding
45. Which winding in a dc-compound
generator that is relatively made of fine wires? shunt field winding
46. What is the primary reason why carbon brushes are preferred over copper brushes in dc motors?
they product less arcing
47. To minimize arcing during starting of dc motors, a resistance should be
added to limit the current in the ____ armature winding
48. Motors whose speed can be easily
controlled. dc motors
49. When a dc motor has no load, what
will happen to the back emf? becomes maximum
50. When can we get a maximum
mechanical power from a dc motor? Eb = 0.5V
51. One cause why the shaft torque is less than the developed armature torque of
a dc motor. friction loss
52. Considered as a variable speed motor
series
53. What is the most common method used in varying the sped of a dc
motor? by varying the field strength
54. In choosing a motor for a particular
application, what characteristic you should consider? speed-torque
55. A motor whose speed increases as the load is increased. differentially compounded
56. Factor(s) that affect iron losses in a dc motor. flux & fied are correct
57. One advantage of a cumulatively compounded motor is that it does not run widely at light loads, this feature is
due to shunt winding
58. In applications where an almost
constant speed is required, a ______ motor is a good choice. dc shunt
59. In applications where a high torque is needed during starting, a ______ motor is preferred.
dc series
60. In applications where sudden heavy loads happen for short duration, a
______ motor is the best choice. cumulatively compounded
61. In motors of the same rating, which
has the least starting torque? dc shunt
62. Factor(s) that affect friction and
winding loses in dc motors. speed
63. In dc motors, power loss is contributed
greatly by copper loss
64. When a motor is overloaded, it will
usually overheat
65. Which motor that produces the highest
increase in torque considering the same increase in current? dc series
66. When an armature opens in dc motor, it may cause intermittent sparking
67. Why do motors take large current during starting? there’s still a low back emf
68. The law which pertains, for any
dielectric reflector, the relationship in which the reflective index is equal to the tangent of the polarizing angle.
Brewster’s angle
69. A law that states the current in a thermoionic diode varies directly with
the three-halves power of anode voltage and inversely with the square of the distance between the
electrodes, providing operating conditions are such that the current is limited only by the spacecharge.
Child’s law
70. The logarithm of the decay constant of an alpha emitter is linearly related to
the logarithm of the range of the alpha particles emitted by it is called _____. Geiger-Nuttal law
71. The law that processing power of a computer is proportional to the square of its cost.
Grosh’s law
72. The law which states an electric motor develops maximum power when Ei =
2Ebk, where Ei is the applied voltage an dEbk is the back-emf. Jacob’s law
73. The law which refers to the strength of the magnetic field at a given point, due to an element of a current-carrying
conductor, is directly proportional to the strength of the current and the projected length of the element and
inversely proportional to the square of the distance of the element from the point in question.
Laplace’s law
74. The law which concerns to a property of mutual inductances. For a given
orientation and environment for two inductors, the value of the mutual inductance does not change,
regardless of the magnitude, frequency, or phase of the currents in the coils. That is, mutual inductance is
subject only to the physical environment surrounding the coils. Neumans law
75. The law that sparkling potential between two parallel place electrodes in a gas I a function of the product of
the gas density and the distance between the electrodes. either Paschen’s rule or Paschen’s
law is right
76. The rule that hysteresis loss in a magnetic material varies directly in proportion with the cube of the
magnetic induction. Rayleigh’s law
77. The thermal-radiation law that shows
the total emissive power of ablackbody to be proportional to the fourth power of the absolute temperature of the
body. Stefan-Boltzmann law
78. The wavelength of luminescence
excited by radiation is always greater than that of the exciting radiation. Stoke’s law
79. It is a law expressing the relationship nbetween a stimulus and the
physiological reaction ir produces: The sensation is proportional to the logarithm of the stimulus
Weber-Fechner law
80. The law indicating that the wavelength of maximum radiation of a blackbody
is inversely proportional to the absolute temperature. either Wien’s first law or Wien’s
displacement law
81. The law showing that the emissive power of a black body is proportional
to the fifth power of absolute temperature is known as either Wien’s radiation law or
Wien’s second law
82. It is an empirical law for the spectral distribution of energy radiated from a
black body at a specified temperatre. Wien’s third law
83. An electromagnetic wave will take a
path that involves the least travel time when propagating between two points. Fermat’s principle
84. The rule that states, during transitions of orbital electrons from higher to lower energy states (accompanied by
the emission of the photons), changes in the inner quantum number may not only e by a factor of 0 r +/- 1.
J rule
85. This is an extension of the two-fluid model of superconductivity, in which it
is assumed that superfluid electrons behave as if the only force acting on them arises from the applied electric
fields, and that the curl of the superfluid current vanishes in the absence of a magnetic field.
London superconductivity theory
86. A formula for the overall transmittance of a signal flow graph in terms of
transmittances of various paths in the graph. Mason’s theorem
87. This applied to a nonradiative transition of an tom from an excited energy state to a lower energy state,
accompanied by the emission of an electron Auger effect
88. Refers to the selective absorption of
electromagnetic waves by a dielectric, due to molecular dipoles Dobye effect
89. The rotation induced in a freely suspended ferromagnetic object when magnetization of the object is
reversed. Einstein-de Has effect
90. The random variations in the output current of an electron tube that has an
oxide-coated cathode, caused by random changes in cathode emission. flicker effect
91. What do you call of the momentary illumination produced when an electric field is applied to a phosphor
previously excited by ultraviolet radiation? Gudden-Pohl effect
92. The ability of ultraviolet radiation to discharge a negatively charged body in a vacuum.
Hallwachs effect
93. The phenomenon whereby current in a gas changes as the result of irradiation
by light is called Joshi effect
94. The variation (caused by the earth’s
magnetic field) of the strength of cosmic rays arriving at different longitudes on the surface of the earth
is known as longitude effect
95. This is the effect when the
magnetization of a helically wound, ferromagnetic wire fluctuates, the tendency for a potential difference to
occur. Mateucci effect
96. _______ refers to the scattering of
monochromatic light (light of a single wavelength) when passed through a transparent substance.
Raman effect
97. This is the ability of an electric current to destroy superconductivity by the
magnetic field that it generates, without raising the cryogenic temperature.
Silsbee effect
98. Electric polarization of a dielectric material being moved in a magnetic
field. Wilson effect
99. What is the two-terminal semi-
conductor device which resembles the behavior of a neuron and allows machines to duplicate some of the
neurological phenomena observed in the human body? neuristor
100. What gadget that electronically aids
the blind which has a camera that scan printed matter and a device forms corresponding raised letters
which can be read with the fingertips? optacon
101. What do you call of a monostable
pentode circuit that generates sharp pulses at an adjustable and accurately timed interval after receipt of a
triggering signal? phantastron
102. What instrument is used to measure the intensity of radiation, such as by determining the amount of
fluorescence produced by that radiation? actinometer
103. _________ referred to a visual sensation experienced by a human subject during the passage of current
through the eye. phosphene
104. It is a pattern that consists of pairs of
white an dark parallel lines, obtained when an electron beam is scattered (diffracted) by a crystalline solid. The
pattern gives information on the structure of the crystal. Kikuchi lines
105. An operational amplifier with double feedback limiters that drive a high-speed relay (1-2 milliseconds) is an
analog computer, usually involved in controlled programming. bang-bang circuit
106. The arrangement of connecting wires in a circuit to prevent undesirable coupling and feedback.
dress
107. What is that device used in biotelemetry for monitoring physiologic
activity of an animal, such as pH values of stomach acid? radio pill
108. Refers to noise produced by erratic jumps of bias current between two levels at random intervals in
operational amplifiers and either semiconductor devices. popcorn noise
109. A conductor in which two oscillating circuits have the same resonant frequency is called
systony
110. Refers to triode electron tube having an anode that can be moved or
vibrated by an externally supplied force. vibrotron