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

A. Positive
B. Negative
C. Zero
D. None of these

In variable frequency, PWM gain

A. Phase lead helps to increase the phase margin of the control loop
B. Phase lag helps to increase the phase margin of the control loop
C. Phase lead helps to decrease the phase margin of the control loop
D. Phase lag helps to decrease the phase margin of the control loop

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

A. A rectifier
B. An inverter
C. A chopper
D. A regulator

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

A. Linear function
B. Non linear function
C. Constant function
D. None of these

The Graetz bridge makes excellent use of ______________?

A. Current transformer
B. Potential transformer
C. Power transformer
D. Scr

DIAC and TRIAC both are semiconductors devices and conduct in____________________?

A. Diac conducts in forward direction and triac conducts in reverse direction
B. Both conducts in forward direction
C. Both conducts in reverse direction
D. Both conducts in either direction

The transfer function of PWM is generally developed in______________?

A. Time domain
B. Frequency domain
C. Either a. or b.
D. None of these

A TRIAC can be turned on with______________?

A. Positive voltage at the gate terminal
B. Negative voltage at the gate terminal
C. Either (a) or (b)
D. None of these

In the SPWM, the modulating signal is___________?

A. Square
B. Sinusoidal
C. Triangular
D. Saw – tooth

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

A. A capacitor
B. A variable resistor
C. An inductor
D. Only (a) and (b)