Power Electronics MCQ

Power electronics refers to the study of electronic switching for controlling the flow of electric power.

A cycloconverter converts

A cycloconverter converts:

  1. AC to DC
  2. DC to AC
  3. DC to DC with different level
  4. AC to AC at different frequencies

Correct answer: 4. AC to AC at different frequencies


The power diode is a

The power diode is a:

  1. One terminal device
  2. Two terminal device
  3. Three terminal device
  4. Four terminal device

Correct answer: 2. Two terminal device


Snubber circuits are employed to

Snubber circuits are employed to:

  1. Reduce the switching power losses
  2. Control the device dv/dt
  3. Avoid breakdowns
  4. All of these

Correct answer: 4. All of these


The Number of PN junctions on thyristor

The Number of PN junctions on thyristor:

  1. Two
  2. Three
  3. Four
  4. Five

Correct answer: 2. Three


An Inverter converts

An inverter converts:

  1. AC to DC
  2. DC to AC
  3. DC to DC with different level
  4. AC to AC at different frequencies

Correct answer: 2. DC to AC

A step-up chopper operates at a duty cycle of 50%. Calculate the output voltage if Vs = 230 V

A step-up chopper operates at a duty cycle of 50%. Calculate the average output voltage of chopper if Vs = 230 V:

  1. 230 V
  2. 460 V
  3. 920 V
  4. 1840 V

Correct answer: 2. 460 V

Solution: Formula: V(o) = 230/(1-0.5)


MCT is current or voltage controlled device

MCT is a __________ controlled device:

  1. Voltage
  2. Current

Correct answer: 1. Voltage


Layer and Junction number on DIAC

The DIAC is a ________ layer, ________ junction device:

  1. Two, Three
  2. Two, Four
  3. Five, Three
  4. Five, Four

Correct answer: 4. Five, Four

During the normal operation of an SCR, the anode with respect to cathode is

During the normal operation of an SCR, the anode is ___________ w.r.t. cathode

  1. Negative
  2. Positive
  3. None of the above

Correct answer: 2. Positive

Which of the following is not an advantage of using RC full wave Triggering Circuit with SCR

Which of the following is not an advantage of using RC full-wave Triggering Circuit with SCR:

  1. Range of firing angle (α) is from 0° to 180°
  2. It produces firing pulses during both cycles of supply
  3. Power dissipation in the gate circuit is more
  4. None of above

Correct answer: 3. Power dissipation in the gate circuit is more

Since the RC-triggering circuit produces prolonged pulses, so the power dissipation in the gate circuit is more

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