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Power Electronics

Study 217 Electrical Engineering MCQs with correct answers and explanations.

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191Electrical EngineeringMedium

During gate recovery time________?

Acharge carriers of J3 junction is removed

Bcharge carriers of J2 junction is swept out

Ccharge carriers of J2 junction recombined

Dcharge carrier of J1 junction removed

Correct answer

C. charge carriers of J2 junction recombined

Explanation

The correct answer is charge carriers of J2 junction recombined.

192Electrical EngineeringMedium

Which one is most suitable power device for high frequency (>100 KHz) switching application?

APower MOSFET

BSchottky diode

CMicrowave transistor

DBJT

Correct answer

A. Power MOSFET

Explanation

The correct answer is Power MOSFET.

193Electrical EngineeringMedium

Form factor of a rectifier is the ratio of ________?

AAverage value of current and voltage to its root mean square value

BPeak value of current and voltage to its root mean square value

CRoot mean square value of voltage and current to its average value

DRoot mean square value of voltage and current to its peak value

Correct answer

C. Root mean square value of voltage and current to its average value

Explanation

The correct answer is Root mean square value of voltage and current to its average value.

194Electrical EngineeringMedium

Voltage commutation circuit can be converted into a current commutation by interchanging the positions of________?

ACapacitor and load

BInductor and capacitor

CDiode and capacitor

DCapacitor and SCR

Correct answer

C. Diode and capacitor

Explanation

The correct answer is Diode and capacitor.

195Electrical EngineeringMedium

Under harmonic free load voltages, the 3 phase VSI________?

ADoes not contains third harmonic

BDoes not contains second harmonic

CDoes not contains fifth harmonic

DDoes not contains seventh harmonic

Correct answer

B. Does not contains second harmonic

Explanation

The correct answer is Does not contains second harmonic.

196Electrical EngineeringMedium

The IGBT resulted in higher switching speed and lower energy losses. It can be used for________?

AUninterruptible power supplies

BAll of these

CInduction heating system

DConstant voltage and frequency power supplies

Correct answer

B. All of these

Explanation

The correct answer is All of these.

197Electrical EngineeringMedium

A capacitive load in voltage source inverters generates ________?

ASmall current spikes and can be reduced by using an inductive filter

BLarge current spikes and can be reduced by using an inductive filter

CSmall current spikes and can be increased by using an inductive filter

DLarge current spikes and can be increased by using an inductive filter

Correct answer

B. Large current spikes and can be reduced by using an inductive filter

Explanation

The correct answer is Large current spikes and can be reduced by using an inductive filter.

198Electrical EngineeringMedium

A string of n parallel SCRs is operated at 72 KA, the rating of each SCR is 1 KA. If derating factor of the string is 0.1. value of n will be________?

A90

B80

C70

D60

Correct answer

B. 80

Explanation

The correct answer is 80.

199Electrical EngineeringMedium

The sum of all phase current in a star connected primary winding with no neutral connection is equal to________?

AZero at all times

BThree times the line current

CPhase current

DThree times the phase current

Correct answer

A. Zero at all times

Explanation

The correct answer is Zero at all times.

200Electrical EngineeringMedium

What may happen high dV / dt________?

AAnyone of these

BUnwanted turn ON

CBoth A and B

DBreakdown of J2 junction

Correct answer

C. Both A and B

Explanation

The correct answer is Both A and B.

During gate recovery time________?

Acharge carriers of J3 junction is removed

Bcharge carriers of J2 junction is swept out

Ccharge carriers of J2 junction recombined

Dcharge carrier of J1 junction removed

Correct answer

C. charge carriers of J2 junction recombined

Explanation

The correct answer is charge carriers of J2 junction recombined.

Form factor of a rectifier is the ratio of ________?

AAverage value of current and voltage to its root mean square value

BPeak value of current and voltage to its root mean square value

CRoot mean square value of voltage and current to its average value

DRoot mean square value of voltage and current to its peak value

Correct answer

C. Root mean square value of voltage and current to its average value

Explanation

The correct answer is Root mean square value of voltage and current to its average value.

A capacitive load in voltage source inverters generates ________?

ASmall current spikes and can be reduced by using an inductive filter

BLarge current spikes and can be reduced by using an inductive filter

CSmall current spikes and can be increased by using an inductive filter

DLarge current spikes and can be increased by using an inductive filter

Correct answer

B. Large current spikes and can be reduced by using an inductive filter

Explanation

The correct answer is Large current spikes and can be reduced by using an inductive filter.