Questions HandOut of Basic Electrical & Electronics Engineering

UNIT-IQues1: Explain independent and dependent energy sources with suitable circuit.

OR Explain independent and dependent voltage source and current source.

OR Differentiate between ideal source and practical source with suitable examples.

Ques2: Differentiate between the following with suitable examples:

Circuit and Network.Active Element and Passive Element.Active Network and Passive Network.Unilateral Element and Bilateral Element.Mesh and Loop.Linear Network and Non Linear Network.Node and Junction.

Ques3: Define the following terms:Branch.Principal Node.Homogeneity.

Ques4: Explain source conversion/transformation. How a practical voltage source is converted into a practical current source? Is it possible to convert an ideal voltage source into ideal current source.

Ques5: Explain KCL and KVL with suitable examples.

Ques6: Explain mesh/loop analysis with suitable illustrations.

Ques7: Explain nodal analysis with suitable examples.

Ques8: Derive/Deduce the relationship to convert star connected resistances into delta connected resistances and vice-versa

OR Derive Star-Delta conversion or transformation.

Ques9: Explain Thevenin’s Theorem with suitable example.

Ques10: Explain Superposition Theorem with suitable example. For which type of circuits does theorem hold?

Ques11: Define the following terms pertaining/related to AC Quantity:

Amplitude.Instantaneous valueAlteration.Cycle.Time Period.Frequency.Form factor.Peak Factor/Crest factor/Amplitude Factor.

Ques12: Define RMS/Virtual/Effective value of an AC quantity. Derive an expression for RMS vale of sinusoidal ac quantity.

Ques13: Define Average/Mean value of an AC quantity. Derive an expression for Average/Mean vale of sinusoidal ac quantity.

Ques14: Explain the term phasor. How it is used to represent the sinusoidal AC quantity? Also mention its importance.

Ques15: Define following terms with suitable examples:

Phase of an AC quantity.Phase Difference.In-phase.Quadrature phase difference.

Ques16: Show that in a purely resistive circuit the supply current is in phase with applied voltage.

ORDerive that in a purely resistive circuit the supply current is in phase with applied voltage.

Ques17: Show that in a purely inductive circuit the supply current is quadrature or 900 lagging with applied voltage.

ORDerive that in a purely inductive circuit the supply current is quadrature or 900 lagging with applied voltage.

Ques18: Show that in a purely capacitive circuit the supply current is quadrature or 900 leading with applied voltage.

ORDerive that in a purely capacitive circuit the supply current is quadrature or 900 leading with applied voltage.

Ques19: Show that the average power consumed over a cycle is zero in the following circuits:

Purely inductive circuit.Purely Capacitive circuit.

Ques20: Show that Current lags voltage in series R-L/inductive circuit.Current leads voltage in series R-C/capacitive circuit

Ques21: Show that the average/mean power consumed over a cycle by an inductive or capacitive

circuit is given by V I cosθ watts, where terms have their usual meanings.

Ques22: Define the term power factor. When is the power factor called as

Unity.Zero power factor lagging.Zero power factor leading.Lagging.Leading.

Ques23: Explain the following terms with suitable examples

Impedance.Admittance.Conductance.Susceptance.

Ques24: Draw the phasor diagram for a series R-L-C circuit energized by a sinusoidal voltage showing the relative positions of the current and applied voltage for the following cases:

X L>X CX L<X CX L=XC

Ques25: Explain or define the following terms: Apparent Power.Active/Mean Power.Reactive/Quadrature/Wattles Power.Also draw the power triangle. Why such terms are not used in dc circuits?

Ques26: Explain resonance. Derive an expression of resonant frequency for following cases:

Series resonant circuit.Parallel resonant/tank circuit.

Ques27: Enumerate the merits of polyhase/three phase system over single phase system.

Ques28: Explain or differentiate between the following:

Balanced System and Unbalanced system.Phase Sequence.Balanced Load and Unbalanced Load.

Ques29: Derive the relationship between line quantities and phase quantities for a balanced star connected system.

Ques30: Derive the relationship between line quantities and phase quantities for a balanced delta connected system.

Ques31: Compare three phase star and delta connection.

UNIT-IIQues1: Explain following laws pertaining to magnetic circuit:

Biot-Savart’s Law.Faraday’s Law of Electromagnetic Induction.Lenz’s Law.

Ques2: Define the following term related to magnetic circuit:

Magnetic Circuit.Magnetic field strength.Magnetizing force.Magneto motive force (MMF).Reluctance.PermeabilityAbsolute Permeability.SusceptibilityMagnetic flux.Magnetic flux density.

Ques3: Compare similarities and dissimilarities between electric circuit and magnetic circuit.

Ques4: Explain statically induced emf and dynamically induced emf with suitable examples.

Ques5: Explain B-H or magnetization curve. Draw the magnetization curve for

Ferromagnetic materialAir or non-magnetic material

Ques6: Explain Hysteresis loop or curve. Draw the hysteresis curve for

Silicon steelFerrite.Hard Steel.Wrought Iron.

Ques7: Explain leakage flux and fringing.

Ques8: Explain series magnetic circuit with suitable examples.

Ques9: Explain parallel magnetic circuit with suitable examples.

Ques10: Explain the working principle of single phase transformer.

OR

On what does the single phase transformer works?

Ques11: Derive the emf equation of single phase transformer and thus derive relationship between turns ratio and voltage ration. Also enlist the assumptions made while deriving the equation.

Ques12: Explain why transformer is called as constant flux device?

ORExplain why primary a current increase as the load on the secondary side is increased?

Ques13: Draw and explain the phasor diagram of an ideal transformer for following cases:

No loadPurely resistive (unity power factor) load.Inductive load.Capacitive load.

Ques14: Draw and explain the phasor diagram of single phase transformer or practical transformer for following cases:

No loadPurely resistive (unity power factor) load.Inductive load.Capacitive load.

Ques15: Classify or differentiate between the following:

Core type and Shell type transformer.Step-up and step-down transformer.Distribution transformer and Power transformer.

Ques16: Explain the followingHow Quality of core material affects the performance of the transformer?Why Conservator and Silica gel breather is used in transformer?Why tappings are provided on transformer winding?Why oil is used in transformer?Why LV winding is placed next to the core?

Ques17: Explain the concept of impedance transformation in single phase transformer.

OR

Show in a single phase transformerZeq=

ZLk2

.Ques18: Draw and explain the exact equivalent circuit of single phase transformer. Also draw the equivalent circuit referred to

Primary sideSecondary side.

Ques19: Explain why direct loading test of transformer is not preferred in laboratory? How will you perform open circuit test and short circuit test on single phase transformer?

Ques20: Explain why open circuit test is performed on low voltage side and short circuit test on high voltage side?

Ques21: Explain various losses that take place in single transformer. On what factors does they depend and how are they minimized?

Ques22: Define efficiency in single phase transformer. Derive an expression of efficiency for single phase transformer.

Ques23: Derive the condition for maximum efficiency in single phase transformer.

Ques24: Define voltage regulation in single phase transformer. Why low value of voltage regulation is desirable?

UNIT-IIIQues1: Explain the constructional details of DC machine.

Ques2: Explain the operation of DC machine as generator and motor.

ORExplain how DC machine works as generator and motor.

Ques3: Classify and explain DC machines along with their circuit diagrams and equations.

ORHow DC machines are classified as

Permanent Magnet DC machine.Separately Excited DC Machine.Self excited DC Machine.

Ques4: Derive the emf equation of multipole DC machine or DC generator.

ORDerive an expression of generated voltage of DC machine in terms of ø, Z, N, P and A.

Ques5: Derive torque equation of DC motor from first principles.

ORDerive torque equation of DC motor in terms of ø, Z, I, P and A.

Ques6: Explain why starting current is high in DC motors?

OR Why starters are required in DC motors?

Ques7: Enlist or enumerate the applications of DC motors.

Ques8: Explain the production of rotating magnetic field in three phase induction motor. What conditions are necessary for its production?

Ques9: Explain in detail the constructional details

of 3−φ Induction machine .

Ques10: Differentiate between three phase squirrel cage induction motor and slip ring induction motor.

Ques10(a): Explain the principle of operation of three phase induction motor. Why a three phase induction motor develops torque at all speeds other than synchronous speed?

Ques11: Explain the term slip in three phase induction motor. Derive an expression for slip.

Ques12: Derive an expression of rotor frequency in terms of slip frequency.

Ques13: Draw and explain the torque-speed and torque slip characteristic of three phase induction

motor and mark the following quantities or parameters

Pull out or break down torque.Starting torque.Normal operating regionStable region.Unstable region.

Ques14: Enlist the applications of three phase induction motor.

OREnlist various applications of squirrel cage and slip ring induction motor.

Ques15: Explain in detail the constructional details

of 3−φ Synchronous Machine .

Ques16: Differentiate between three phase salient pole synchronous machine and smooth cylindrical type synchronous machine.

Ques17: Differentiate between three phase synchronous motor and three phase induction motor.

Ques18: Explain the principle of three phase synchronous machine as generator.

ORExplain the principle of operation of three phase synchronous generator.

Ques19: Define synchronous speed in three phase machine.

Ques20: Derive emf equation of three phase synchronous generator or alternator.

Ques21: Write an expression of emf equation of three phase induction motor.

UNIT-IVQues1: Explain various number systems with suitable examples.

ORExplain the following number system with supportive examples:

Decimal Number system.Binary Number System.Octal Number system.Hexadecimal Number system.

Ques2: What do you understand by 1’s complement and 2’s complement of binary number system?

Ques3: Explain in detail the conversion of various number systems used in digital electronics.

Ques3: Write short notes on Floating point numbers.Signed Numbers.

Ques4: Give the truth table and logic realization of following gates:

OR ANDNOT NANDNORX-OR

Ques5: Why NAND gate is called as universal gate? How it can be used to implement

OR GateAND GateNOT Gate.

Ques6: Show how a NOR gate can be used to realize

NAND gateNOT gate

Ques7: State and prove De-Morgan’s Theorem and illustrate them using suitable examples.

Ques8: Explain the working of half adder with the help of circuit diagram and truth table. Obtain the expression for sum and carry.

Ques9: Explain the working of full adder with the help of circuit diagram and truth table. Obtain the expression for sum and carry.

Ques10: Explain how a full adder can be implemented or realized using two half adder.

UNIT-VQues1: Classify the materials as

Conductors.Insulators.Semiconductors.along with examples.

Ques2: What do you understand by intrinsic (pure) semiconductor and extrinsic semiconductor?

Ques3: Which impurities are added in intrinsic semiconductor to make n-type and p-type semiconductor?

Ques4: Explain doping in semiconductor. Why it is required?

Ques5: Explain current conduction mechanism in n-type semiconductor.

Ques6: Explain p-n junction. How it is formed? OR

Explain the formation of p-n junction. Illustrate following terms pertaining to p-n junction

Depletion layerBarrier potentialMajority Carriers.Minority Carriers.

Ques7: Explain the operation of p-n junction diode under forward biased condition.

Ques8: Explain the operation of p-n junction diode under reverse biased condition.

Ques9: Define the following terms in relation to diode:

Drift current.Diffusion current.Forward Dynamic Resistance.Reverse Leakage Current.Avalanche Breakdown.

Ques10: Explain V-I characteristics of a diode under forward biased and reverse biased.

Ques11: Explain the constructional feature of a n-p-n or p-n-p transistor. Why base layer is lightly doped and emitter layer is highly doped?

Ques12: Explain the basic principle of operation of n-p-n BJT transistor.

Ques13: Enlist three configurations of transistor and explain any one in detail.

ORExplain BJT transistor characteristic for CE configuration.

Ques14: Draw input and output characteristics of BJT. Also explain its operation under following regions

Active RegionCut-off RegionSaturation Region.

Ques15: Define α and β of BJT and establish relationship between them.

OR

Derive for BJT α= β

1+βor β= α

1−α .

Ques16: Compare CB, CB and CE configurations of transistor with reference to the following parameters

Input Resistance.Output Resistance.Input Current.Output Current.Current Amplification Factor.Current Gain.Voltage Gain.

Ques17: What do you understand by DC biasing of transistor? Why it is required? Enlist various methods of biasing a BJT.