Quiz  /  Power Electronics Gate & PSU MCQ Questions With Answers

  • 1. 
    Name the below given circuit.

  • Single-phase dual converter circulating current type
  • Single-phase dual converter non-circulating current type
  • Three-phase dual converter non-circulating current type
  • Three-phase dual converter circulating current type

  • 2. 
    In case of TRC (Time Ratio Control), _________ is varied

  • firing angle
  • load cycle
  • duty cycle
  • load angle

  • 3. 
    In general, only ideal power switches generating power losses during their operation.

  • True
  • False

  • 4. 
    A diode is an

  • active switch
  • passive switch
  • both (a) and (b)
  • none of these

  • 5. 
    Which of the following is a two quadrant switch?

  • MOSFET
  • IGBT
  • BJT
  • All of the above

  • 6. 
    What is the name of power loss of a semiconductor device that occurs during the on-state?

  • Blocking state power loss
  • Forward conduction power loss
  • Switching power loss
  • None the above answers

  • 7. 
    The load voltage of a chopper can be controlled by varying the..................

  • duty cycle
  • firing angle
  • reactor position
  • extinction angle

  • 8. 
    1. In case of three-phase dual converter, one of the converter circuits is fired at an angle of 60°. For both the converter circuits to have equal average output voltage, what is the value of the firing angle for the other converter circuit?

  • 60°
  • 120°
  • 100°
  • Insufficient data

  • 9. 
    Forward recovery voltage appears due to higher ohmic drop in the ______________ region of a power diode in the beginning of the Turn On process.

  • forward
  • reverse
  • drift
  • potential barrier

  • 10. 
    A thyristor is a ________________ carrier semi controlled device.

  • majority
  • minority
  • both (a) and (b)
  • none of the above

  • 11. 
    If V1 and V2 are the instantaneous voltages of the two converter circuits in the dual convert, then the output voltage is

  • 2(V1 + V2)
  • V1 + V2
  • V1 – V2
  • (V1 + V2)/2

  • 12. 
    For the same firing angle and input voltage the half controlled converter gives ___________________ output voltage form factor compared to a fully controlled converter.

  • lower
  • higher
  • constant
  • variable

  • 13. 
    The input displacement factor of a single phase fully controlled bridge converter in the continuous conduction mode is equal to the cosine of the ________ angle.

  • extinction
  • firing
  • conduction
  • load

  • 14. 
    In the three-phase bridge inverter, each step consists of

  • 30°
  • 60°
  • 90°
  • will depend on firing angle

  • 15. 
    The maximum DC voltage rating (VRDC) of a power diode is useful for selecting ________________ diodes in a DC-DC chopper.

  • snubber diodes
  • reverse recovery diodes
  • freewheeling diodes
  • fast recovery diodes

  • 16. 
    In the circuit shown in figure

  • only the negative cycle can be controlled
  • only the positive cycle can be controlled
  • both the cycles can be controlled
  • none of the mentioned

  • 17. 
    The gate-source voltage at which the ________________ layer in a MOSFET is formed is called the ________________ voltage.

  • drift layer, breakover
  • depletion layer, threshold
  • inversion, threshold
  • inversion, breakover

  • 18. 
    In voltage source inverters

  • load voltage Vo depends on load impedance but load current Io does not depend on load impedance Z
  • both Vo and Io depends on Z
  • Io depends on Z but Vo does not depend
  • none of these

  • 19. 
    The magnitude of the forward recovery voltage is typically of the order of few ______________ of volts.

  • ones
  • tens
  • hundreds
  • thousands

  • 20. 
    Which of the following is an active switch?

  • MOSFET
  • IGBT
  • Both (a) and (b)
  • Either (a) or (b)

  • 21. 
    In a single phase voltage source square wave inverter with inductive load, the waveform of the load current will be

  • sinusoidal
  • trapezoidal
  • square
  • triangular

  • 22. 
    Schottky diodes have no __________________ transient and very little _________________ transient.

  • turn off, turn on
  • turn on, turn off
  • both (a) and (b)
  • none of the above

  • 23. 
    The i-v characteristics of a power diode for large forward current is __________ .

  • straight line
  • linear
  • nonlinear
  • parabolic

  • 24. 
    For a given forward current the reverse recovery current of a Power Diode ______________ with the rate of decrease of the forward current.

  • decreases
  • constant
  • increases
  • none of the above

  • 25. 
    Enhancement type MOSFETs are normally ________________devices while depletion type MOSFETs are normally ________________ devices.

  • on, off
  • off, on
  • both (a) and (b)
  • none of the above

  • 26. 
    In single phase full wave ac voltage regulator, varying the firing angle from a to 180 can vary the rms output voltage from

  • Vs to Vs/4
  • Vs to Vs/2
  • Vs to 3Vs/2
  • Vs to 0

  • 27. 
    Application of ac voltage controller using integral cycle method is in

  • induction heating
  • dielectric heating
  • gas furnace
  • none of these

  • 28. 
    To allow power conversion, we can arrange all power switches in the converter freely.

  • True
  • False

  • 29. 
    The process of commutating a SCR by applying a reverse voltage to an SCR through a previously charged capacitor is called as

  • capacitor commutation
  • forced commutation
  • voltage commutation
  • current commutation
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