Power Electronics MCQs

Option A: Identical to line voltage in a VSI

Option B: Identical to line current in VSI

Option C: Identical to phase voltage in VSI

Option D: Identical to phase voltage in CSI

Correct Answer: Identical to line voltage in a VSI ✔

Option A: Dependent on the load current

Option B: Dependent on the voltage

Option C: Dependent on both the load current and load voltage behind the short circuit current

Option D: Independent on both the load current and load voltage

Correct Answer: Dependent on both the load current and load voltage behind the short circuit current ✔

Option A: Suppressing emissions

Option B: Reducing the efficiency of the coupling path

Option C: Reducing the susceptibility of the receptor

Option D: All of these

Correct Answer: All of these ✔

A. silicon has large leakage current than germanium
B. silicon has small leakage current than germanium
C. silicon has small leakage voltage than germanium
D. silicon has large leakage voltage than germanium

Correct Answer: . silicon has small leakage current than germanium ✔

Option A: two SCR’s in parallel opposition

Option B: two SCR’s in series

Option C: three SCR’s in series

Option D: four SCR’s in series

Correct Answer: two SCR’s in parallel opposition ✔

Option A: Duty ratio only

Option B: Frequency only

Option C: Duty ratio and frequency

Option D: Duty ratio, frequency and time delay

Correct Answer: Duty ratio, frequency and time delay ✔

Option A: Electrical power developed in armature – copper losses

Option B: Mechanical power input – iron and friction losses

Option C: Electrical power developed in armature – iron and copper losses

Option D: Mechanical power input – iron and friction losses – copper losses

Correct Answer: Mechanical power input – iron and friction losses ✔

Option A: It will rotate at the same speed as that with its field winding closed

Option B: It will rotate at less speed as that with its field winding closed

Option C: It will rotate at dangerously high speed

Option D: None of these

Correct Answer: It will rotate at dangerously high speed ✔

Option A: Load survey method

Option B: Mathematical method

Option C: Statistical method

Option D: Economic parameters

Correct Answer: Statistical method ✔

Option A: Frequencies above 20 kHz

Option B: Frequencies above 1000 kHz

Option C: Frequencies less than 10 Hz

Option D: 50 Hz frequency

Correct Answer: 50 Hz frequency ✔

Option A: Cmin = V / ( Vr L f2 )

Option B: Cmin= ( 1 – D ) V / ( Vr L f2 )

Option C: Cmin= ( 1 – 2 D ) V / 32 ( Vr L f2 )

Option D: Cmin= ( 1 – 2 D ) V / 42 ( Vr L f2 )

Correct Answer: Cmin= ( 1 – 2 D ) V / 32 ( Vr L f2 ) ✔

Option A: Metal – oxide semiconductor field effect transistor

Option B: Molybdenum – oxide semiconductor field effect transistor

Option C: Metal – oxide silicon field effect transistor

Option D: Metal – oxide semiconductor field effect transmitter

Correct Answer: Metal – oxide semiconductor field effect transistor ✔

Option A: Flyback capacitor

Option B: Flyback resistor

Option C: Flyback transformer

Option D: Flyback transistor

Correct Answer: Flyback transformer ✔

Option A: Large number of reactive component

Option B: Low stress on switch

Option C: Low stress on capacitor

Option D: None of these

Correct Answer: None of these ✔

Option A: Only minority carriers

Option B: Only majority carriers

Option C: Both minority and majority carriers

Option D: None of these

Correct Answer: Only majority carriers ✔

Option A: Divert the collector current during turn – off

Option B: Improves the reverse bias safe operating area

Option C: Dissipates a fair amount of switching power

Option D: All of these

Correct Answer: All of these ✔

Option A: High dv / dt, low di / dt

Option B: Low dv / dt, low di / dt

Option C: Low dv / dt, high di / dt

Option D: High dv / dt, high di / dt

Correct Answer: High dv / dt, high di / dt ✔

Option A: Motoring mode operation

Option B: Braking mode operation

Option C: Regenerative mode operation

Option D: None of these

Correct Answer: Regenerative mode operation ✔

Option A: Boost single – phase power factor converter

Option B: A buck dc – dc converter to reduce ripple in the intermediate dc bus capacitor

Option C: Both A. and B.

Option D: None f these

Correct Answer: C. Both A. and B. ✔

Option A: High power inverters

Option B: Rectifiers

Option C: Low power inverters

Option D: Only A. and B.

Correct Answer: D. Only A. and B. ✔

Option A: Multiple of two

Option B: Odd multiple of three

Option C: Odd multiple of five

Option D: Odd multiple of seven

Correct Answer: Odd multiple of three ✔

Option A: Can control the load voltage

Option B: Cannot control the load voltage

Option C: Cannot control the load voltage except by means of dc link voltage

Option D: Cannot control the load voltage except by means of dc link current

Correct Answer: Cannot control the load voltage ✔

Option A: Three inductances

Option B: Three capacitances

Option C: Three resistance

Option D: Three transistors

Correct Answer: Three inductances ✔

Option A: 120 degree after the zero crossing of the corresponding line voltages

Option B: 60 degree after the zero crossing of the corresponding line voltages

Option C: 120 degree before the zero crossing of the corresponding line voltages

Option D: 60 degree before the zero crossing of the corresponding line voltages

Correct Answer: 60 degree after the zero crossing of the corresponding line voltages ✔

Option A: Susceptibility

Option B: Emission

Option C: Interference

Option D: Electromagnetic compatibility

Correct Answer: Electromagnetic compatibility ✔

Option A: Immunity

Option B: Emission

Option C: Interference

Option D: Electromagnetic compatibility

Correct Answer: Immunity ✔

Option A: Average value of the output inductor current

Option B: Product of an average inductor current and a function of duty ratio

Option C: Either A. or B.

Option D: None of these

Correct Answer: C. Either A. or B. ✔

Option A: Electric traction

Option B: Electric vehicles

Option C: Machine tools

Option D: All of these

Correct Answer: All of these ✔

Option A: Equal to the average power supplied by the dc source

Option B: Greater than the average power supplied by the dc source

Option C: Lesser than the average power supplied by the dc source

Option D: Equal to the average power supplied by the ac source

Correct Answer: Equal to the average power supplied by the dc source ✔

Option A: Lighting and heating control

Option B: On – line transformer tap changing

Option C: Soft starting

Option D: All of these

Correct Answer: All of these ✔

Option A: Top switch of each leg is on at any instant

Option B: Bottom switch of each leg is on at any instant

Option C: Either A. or B.

Option D: None of these

Correct Answer: C. Either A. or B. ✔

Option A: A capacitor

Option B: A variable resistor

Option C: An inductor

Option D: Only (a) and (b)

Correct Answer: Only (a) and (b) ✔

Option A: Square

Option B: Sinusoidal

Option C: Triangular

Option D: Saw – tooth

Correct Answer: Sinusoidal ✔

Option A: Positive voltage at the gate terminal

Option B: Negative voltage at the gate terminal

Option C: Either (a) or (b)

Option D: None of these

Correct Answer: Either (a) or (b) ✔

Option A: Time domain

Option B: Frequency domain

Option C: Either A. or B.

Option D: None of these

Correct Answer: C. Either A. or B. ✔

Option A: DIAC conducts in forward direction and TRIAC conducts in reverse direction

Option B: Both conducts in forward direction

Option C: Both conducts in reverse direction

Option D: Both conducts in either direction

Correct Answer: Both conducts in either direction ✔

Option A: Current transformer

Option B: Potential transformer

Option C: Power transformer

Option D: SCR

Correct Answer: Power transformer ✔

Option A: Linear function

Option B: Non linear function

Option C: Constant function

Option D: None of these

Correct Answer: None of these ✔

Option A: A rectifier

Option B: An inverter

Option C: A chopper

Option D: A regulator

Correct Answer: An inverter ✔

Option A: Phase lead helps to increase the phase margin of the control loop

Option B: Phase lag helps to increase the phase margin of the control loop

Option C: Phase lead helps to decrease the phase margin of the control loop

Option D: Phase lag helps to decrease the phase margin of the control loop

Correct Answer: Phase lead helps to increase the phase margin of the control loop ✔

Option A: Positive

Option B: Negative

Option C: Zero

Option D: None of these

Correct Answer: Positive ✔

Option A: AC input power to the transformer volt – amp rating required by secondary

Option B: AC input power to the transformer volt – amp rating required by primary

Option C: DC output power to the transformer volt – amp rating required by secondary

Option D: DC output power to the transformer volt – amp rating required by primary

Correct Answer: C. DC output power to the transformer volt – amp rating required by secondary ✔

Option A: A switching pulse generator and a shorting pulse generator

Option B: A shorting pulse distributor

Option C: A switching and shorting pulse combination

Option D: All of these

Correct Answer: All of these ✔

Option A: 60 degree

Option B: 90 degree

Option C: 120 degree

Option D: 150 degree

Correct Answer: 120 degree ✔

Option A: Rms value of the ac component of load voltage to the dc voltage

Option B: Average value of the ac component of load voltage to the peak value of voltage

Option C: Average value of the dc component of load voltage to the ac voltage

Option D: Peak value of the dc component of load voltage to the ac voltage

Correct Answer: Rms value of the ac component of load voltage to the dc voltage ✔

Option A: Root mean square value of voltage and current to its peak value

Option B: Root mean square value of voltage and current to its average value

Option C: Average value of current and voltage to its root mean square value

Option D: Peak value of current and voltage to its root mean square value

Correct Answer: Root mean square value of voltage and current to its average value ✔

Option A: By applying a gate pulse and turned off only when current becomes zero

Option B: And turned off by applying gate pulse

Option C: By applying a gate pulse and turned off by removing the gate pulse

Option D: By making current non zero and turned off by making current zero

Correct Answer: By applying a gate pulse and turned off only when current becomes zero ✔

Option A: Two SCR’s connected in reverse parallel

Option B: Two SCR’s connected in parallel

Option C: Two SCR’s connected in series

Option D: Two BJT’s connected in series

Correct Answer: Two SCR’s connected in reverse parallel ✔

Option A: both as forward characteristics

Option B: both as reverse characteristics

Option C: former as forward characteristics and later as reverse characteristics

Option D: former as reverse characteristics and later as forward characteristics

Correct Answer: former as forward characteristics and later as reverse characteristics ✔

Option A: as static conductor

Option B: for power control

Option C: for speed control of dc shunt motor

Option D: All of these

Correct Answer: All of these ✔

Option A: breakdown voltage

Option B: peak reverse voltage

Option C: holding current

Option D: latching current

Correct Answer: holding current ✔

Option A: voltage sensitive load from excessive dc power supply output voltages

Option B: current sensitive load from excessive dc power supply output voltages

Option C: voltage sensitive load from excessive ac power supply output voltages

Option D: current sensitive load from excessive ac power supply output voltages

Correct Answer: voltage sensitive load from excessive dc power supply output voltages ✔

Option A: Diode

Option B: BJT

Option C: SCR

Option D: TRIAC

Correct Answer: TRIAC ✔

Option A: Second harmonic

Option B: Third harmonic

Option C: Fifth harmonic

Option D: Do not produce harmonics

Correct Answer: Do not produce harmonics ✔

Option A: Unidirectional

Option B: Bidirectional

Option C: Fixed voltage polarity

Option D: Only (a) and (c)

Correct Answer: Only (a) and (c) ✔

Option A: Sine wave

Option B: Square wave

Option C: Saw – tooth wave

Option D: Trapezoidal wave

Correct Answer: Square wave ✔

Option A: Uninterruptible power supplies

Option B: Induction heating system

Option C: Constant voltage and frequency power supplies

Option D: All of these

Correct Answer: All of these ✔

Option A: There is always a path for the dc current independent of the ac line

Option B: There is always a path for the ac current independent of the ac line

Option C: There is always a path for the dc current dependent of the ac line

Option D: There is always a path for the ac current independent of the ac line

Correct Answer: There is always a path for the dc current independent of the ac line ✔

Option A: Current sensor across IGBT

Option B: Voltage sensor across IGBT

Option C: Current sensor in series with IGBT

Option D: Voltage sensor in series with IGBT

Correct Answer: Current sensor in series with IGBT ✔

Option A: Passive filter

Option B: Active filter

Option C: Both passive and active filters

Option D: None of these

Correct Answer: Both passive and active filters ✔

Option A: Drop across the collector junction

Option B: Drop across the drift region

Option C: Drop across MOSFET portion

Option D: All of these

Correct Answer: All of these ✔

Option A: Continuous signal

Option B: Large isolating pulse transformer

Option C: A train of pulses

Option D: None of these

Correct Answer: A train of pulses ✔

Option A: 180 degree

Option B: 190 degree

Option C: 200 degree

Option D: 210 degree

Correct Answer: 210 degree ✔

Option A: Both harmonic distortion and quality of input current increases

Option B: Harmonic distortion increases and quality of input current decreases

Option C: Harmonic distortion decreases and quality of input current increases

Option D: Both harmonic distortion and quality of input current decreases

Correct Answer: Harmonic distortion increases and quality of input current decreases ✔

Option A: 2nd

Option B: 3rd

Option C: 5th

Option D: 7th

Correct Answer: 2nd ✔

Option A: Current controlled unipolar device

Option B: Voltage controlled unipolar device

Option C: Current controlled bipolar device

Option D: Voltage controlled bipolar device

Correct Answer: Voltage controlled unipolar device ✔

Option A: Both rectifiers provides positive current to the load

Option B: Both rectifiers provide negative current to the load

Option C: One rectifiers provide positive current to the load and the other negative current

Option D: One rectifier provide positive current to the source and the other negative current to the load

Correct Answer: Both rectifiers provides positive current to the load ✔

Option A: More than that of MOSFET

Option B: Lower than that of MOSFET

Option C: Equal to that of MOSFET

Option D: Equal to that of BJT

Correct Answer: Lower than that of MOSFET ✔

Option A: A high on – resistance switch can be added in parallel

Option B: A low on – resistance switch can be added in parallel

Option C: A high on – resistance switch can be added in series

Option D: A low on – resistance switch can be added in series

Correct Answer: D. A low on – resistance switch can be added in series ✔

a. Reversal of power can be controlled by firing angle
b. Very good dynamic behavior
c. They can link two AC system operating unsynchronized
d. All of these

Correct Answer: d. All of these ✔

Option A: A parallel combination of controllable switch and a diode is used

Option B: A parallel combination of controllable switch and capacitor is used

Option C: A series combination of controllable switch and a diode is used

Option D: A series combination of controllable switch and a capacitor is used

Correct Answer: A parallel combination of controllable switch and a diode is used ✔

Option A: Unidirectional

Option B: Bidirectional

Option C: Either (a) or (b)

Option D: Non directional

Correct Answer: Unidirectional ✔

Option A: Negatively affected by firing angle

Option B: Negatively affected by distortion of the input current

Option C: Positively affected by both firing angle and distortion of the input current

Option D: Both (a) and (b)

Correct Answer: Both (a) and (b) ✔

Option A: Power supplies

Option B: Ups

Option C: Multilevel configuration

Option D: All of these

Correct Answer: All of these ✔

Option A: Motors

Option B: Switches, radio interferences

Option C: Computers, digital electronics

Option D: All of these

Correct Answer: All of these ✔

Option A: Square AC output voltage

Option B: Sine AC output voltage

Option C: Triangular AC output voltage

Option D: Trapezoidal AC output voltage

Correct Answer: Square AC output voltage ✔

Option A: Noise

Option B: Distortion

Option C: Interference

Option D: All of these

Correct Answer: Noise ✔

Option A: 2nd

Option B: 3rd

Option C: 5th

Option D: 7th

Correct Answer: 2nd ✔

Option A: Permanent angle converter

Option B: Phase angle converter

Option C: Phase angle commutation

Option D: Phase and commutation

Correct Answer: Phase angle converter ✔

Option A: Two dimensional functions

Option B: Three dimensional functions

Option C: One dimensional functions

Option D: All of these

Correct Answer: Two dimensional functions ✔

Option A: AC – DC

Option B: DC – DC

Option C: DC – AC

Option D: All of these

Correct Answer: All of these ✔

Option A: Zero

Option B: Switches between – 1 / 2 and + 1 / 2

Option C: Switches between – 1 and + 1

Option D: Switches between 0 and + 1

Correct Answer: B. Switches between – 1 / 2 and + 1 / 2 ✔

Option A: One

Option B: two

Option C: Three

Option D: Four

Correct Answer: two ✔

Option A: Directly proportional to their harmonic order

Option B: Inversely proportional to their harmonic order

Option C: Not related to their harmonic order

Option D: None of these

Correct Answer: Inversely proportional to their harmonic order ✔

Option A: Only amplitude of voltage is controllable

Option B: Only phase is controllable

Option C: Both amplitude and phase is controllable

Option D: Amplitude, phase and frequency of voltages should always be controllable

Correct Answer: Amplitude, phase and frequency of voltages should always be controllable ✔

Option A: Does not contains second harmonic

Option B: Does not contains third harmonic

Option C: Does not contains fifth harmonic

Option D: Does not contains seventh harmonic

Correct Answer: Does not contains second harmonic ✔

Option A: Sine wave

Option B: Square wave

Option C: Triangular wave

Option D: Trapezoidal wave

Correct Answer: Sine wave ✔

Option A: Identical to line voltage in a VSI

Option B: Identical to line current in VSI

Option C: Identical to phase voltage in VSI

Option D: Identical to phase voltage in CSI

Correct Answer: Identical to line voltage in a VSI ✔

Option A: Sawtooth carrier

Option B: Inverted sawtooth carrier

Option C: Triangle carrier

Option D: All of these

Correct Answer: All of these ✔

Option A: 5

Option B: 7

Option C: 11

Option D: All of these

Correct Answer: All of these ✔

Option A: Small current spikes and can be reduced by using an inductive filter

Option B: Large current spikes and can be increased by using an inductive filter

Option C: Small current spikes and can be increased by using an inductive filter

Option D: Large current spikes and can be reduced by using an inductive filter

Correct Answer: Large current spikes and can be reduced by using an inductive filter ✔

Option A: One

Option B: Three

Option C: Six

Option D: Nine

Correct Answer: Six ✔

Option A: Obtain an dc output waveform from a dc power supply

Option B: Obtain an ac output waveform from a dc power supply

Option C: Obtain an dc output waveform from a dc power supply

Option D: Obtain an ac output waveform from a ac power suppl

Correct Answer: Obtain an ac output waveform from a dc power supply ✔

Option A: Dependent on the load current

Option B: Dependent on the voltage

Option C: Dependent on both the load current and load voltage behind the short circuit current

Option D: Independent on both the load current and load voltage

Correct Answer: Dependent on both the load current and load voltage behind the short circuit current ✔

Option A: Voltage mode control

Option B: Current mode control

Option C: Hysteric control

Option D: All of these

Correct Answer: All of these ✔

Option A: Large overlapping takes place

Option B: Small overlapping operation

Option C: No overlapping operation

Option D: None of these

Correct Answer: No overlapping operation ✔

Option A: V 0 = V s

Option B: V 0 = D V s

Option C: V 0 = V s / D

Option D: V 0 = V s / ( 1 – D )

Correct Answer: V 0 = D V s ✔

Option A: Suppressing emissions

Option B: Reducing the efficiency of the coupling path

Option C: Reducing the susceptibility of the receptor

Option D: All of these

Correct Answer: All of these ✔

Option A: AC – DC converters

Option B: AC – AC converters

Option C: DC – AC converters

Option D: DC – DC converters

Correct Answer: D. DC – DC converters ✔

Option A: Decays as 1 / R, where R is the separation distance between the emitter and the receptor

Option B: Decays as R, where R is the separation distance between the emitter and the receptor

Option C: Decays as 1 / 2 R, where R is the separation distance between the emitter and the receptor

Option D: Decays as 2R, where R is the separation distance between the emitter and the receptor

Correct Answer: Decays as 1 / R, where R is the separation distance between the emitter and the receptor ✔