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Power Electronics

Study 217 Electrical Engineering MCQs with correct answers and explanations.

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41Electrical EngineeringMedium

Snubber circuit is used with SCR________?

Ain series

Beither series or parallel

Canti parallel

Din parallel

Correct answer

D. in parallel

Explanation

The correct answer is in parallel.

42Electrical EngineeringMedium

A MOSFET, for its conduction uses________?

AOnly majority carriers

BBoth minority and majority carriers

CNone of these

DOnly minority carriers

Correct answer

A. Only majority carriers

Explanation

The correct answer is Only majority carriers.

43Electrical EngineeringMedium

If all the SCR’s of 3 phase PAC is replaced by diodes, they would be triggered________?

A120 degree before the zero crossing of the corresponding line voltages

B120 degree after the zero crossing of the corresponding line voltages

C60 degree before the zero crossing of the corresponding line voltages

D60 degree after the zero crossing of the corresponding line voltages

Correct answer

D. 60 degree after the zero crossing of the corresponding line voltages

Explanation

The correct answer is 60 degree after the zero crossing of the corresponding line voltages.

44Electrical EngineeringMedium

Thermal voltage VT can be given by________?

AqT/K

B(K2/q)(T + 1/T – 1)

CKT/q

DKq/T

Correct answer

C. KT/q

Explanation

The correct answer is KT/q.

45Electrical EngineeringMedium

Bidirectional semiconductor device is________?

ATRIAC

BDiode

CSCR

DBJT

Correct answer

A. TRIAC

Explanation

The correct answer is TRIAC.

46Electrical EngineeringMedium

A carrier based PWM technique in CSI is composed of________?

AA switching and shorting pulse combination

BAll of these

CA shorting pulse distributor

DA switching pulse generator and a shorting pulse generator

Correct answer

B. All of these

Explanation

The correct answer is All of these.

47Electrical EngineeringMedium

The ability of an electronic system to function properly in its intended electromagnetic environment and should not be a source of pollution to that electromagnetic environment is known as________?

AInterference

BElectromagnetic compatibility

CSusceptibility

DEmission

Correct answer

B. Electromagnetic compatibility

Explanation

The correct answer is Electromagnetic compatibility.

48Electrical EngineeringMedium

When a large surge current of very short duration flows through a thyristor then which one of the following device will operate to protect the thyristor ________?

AVoltage clamping device

BFast acting current limiting device (FACL fuse)

CCB

DSnubber circuit

Correct answer

B. Fast acting current limiting device (FACL fuse)

Explanation

The correct answer is Fast acting current limiting device (FACL fuse).

49Electrical EngineeringMedium

MOSFET stands for________?

AMetal – oxide semiconductor field effect transmitter

BMetal – oxide silicon field effect transistor

CMolybdenum – oxide semiconductor field effect transistor

DMetal – oxide semiconductor field effect transistor

Correct answer

D. Metal – oxide semiconductor field effect transistor

Explanation

The correct answer is Metal – oxide semiconductor field effect transistor.

50Electrical EngineeringMedium

In reverse blocking mode of a thyristor________?

Ajunction J3 is in forward bias and J1, J2 in reverse bias.

Bjunction J1, J3 is in reverse bias and J2 is in forward bias.

Cjunction J1 and J2 is in forward bias and J3 is in reverse bias.

Djunction J2 is in reverse bias and J1, J3 is in forward bias.

Correct answer

B. junction J1, J3 is in reverse bias and J2 is in forward bias.

Explanation

The correct answer is junction J1, J3 is in reverse bias and J2 is in forward bias..

If all the SCR’s of 3 phase PAC is replaced by diodes, they would be triggered________?

A120 degree before the zero crossing of the corresponding line voltages

B120 degree after the zero crossing of the corresponding line voltages

C60 degree before the zero crossing of the corresponding line voltages

D60 degree after the zero crossing of the corresponding line voltages

Correct answer

D. 60 degree after the zero crossing of the corresponding line voltages

Explanation

The correct answer is 60 degree after the zero crossing of the corresponding line voltages.

MOSFET stands for________?

AMetal – oxide semiconductor field effect transmitter

BMetal – oxide silicon field effect transistor

CMolybdenum – oxide semiconductor field effect transistor

DMetal – oxide semiconductor field effect transistor

Correct answer

D. Metal – oxide semiconductor field effect transistor

Explanation

The correct answer is Metal – oxide semiconductor field effect transistor.

In reverse blocking mode of a thyristor________?

Ajunction J3 is in forward bias and J1, J2 in reverse bias.

Bjunction J1, J3 is in reverse bias and J2 is in forward bias.

Cjunction J1 and J2 is in forward bias and J3 is in reverse bias.

Djunction J2 is in reverse bias and J1, J3 is in forward bias.

Correct answer

B. junction J1, J3 is in reverse bias and J2 is in forward bias.

Explanation

The correct answer is junction J1, J3 is in reverse bias and J2 is in forward bias..