Electrical Engineering Mcqs Practice Test

Question 1

A step – down choppers can be used in___________?

Accepted Answer

D. All of these

Question 2

In a lossless inverter, the average power absorbed in one period by the load must be__________?

Accepted Answer

A. Equal to the average power supplied by the dc source

Question 3

The ac voltage controller can be used for ___________?

Accepted Answer

D. All of these

Question 4

In a full bridge VSI, in order to avoid the short circuit across the DC bus and the undefined AC output voltage condition, the modulating technique should ensure that___________?

Accepted Answer

C. Either A. or B.

Question 5

The phase angle of gate signal in TRIAC can be shifted by using_____________?

Accepted Answer

D. Only (a) and (b)

Question 6

In the SPWM, the modulating signal is___________?

Accepted Answer

B. Sinusoidal

Question 7

A TRIAC can be turned on with______________?

Accepted Answer

C. Either (a) or (b)

Question 8

The transfer function of PWM is generally developed in______________?

Accepted Answer

C. Either A. or B.

Question 9

DIAC and TRIAC both are semiconductors devices and conduct in____________________?

Accepted Answer

D. Both conducts in either direction

Question 10

The Graetz bridge makes excellent use of ______________?

Accepted Answer

C. Power transformer

Question 11

In constant frequency PWM, at perturbation the amplitude of the sinusoidal component is a___________?

Accepted Answer

D. None of these

Question 12

If the firing angle becomes negative, then the rectifier begins to work as_______________?

Accepted Answer

B. An inverter

Question 13

In variable frequency, PWM gain

Accepted Answer

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

Question 14

In a 3 phase half wave rectifier, when firing angle is less than 90 degree, then the average dc output voltage becomes__________________?

Accepted Answer

A. Positive

Question 15

Transformer utilization factor is a measure of the merit of a rectifier circuit. It is the ratio of_______________?

Accepted Answer

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

Question 16

A carrier based PWM technique in CSI is composed of____________?

Accepted Answer

D. All of these

Question 17

In a square – wave operation of 3 phase CSIs, the power values are on for___________?

Accepted Answer

C. 120 degree

Question 18

Ripple factor is the ratio of______________________?

Accepted Answer

A. Rms value of the ac component of load voltage to the dc voltage

Question 19

Form factor of a rectifier is the ratio of ______________?

Accepted Answer

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

Question 20

Silicon controlled rectifier can be turned on____________?

Accepted Answer

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