Basic Power Electronics (22427) Quiz

25 Questions | Total Attempts: 48

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Basic Power Electronics (22427) Quiz

Mr. Gavde P. B. M. E. (Electronics) (Lecturer in Electronics) Electronics & communication Department Government Polytechnic,Beed


Questions and Answers
  • 1. 
    Latching current define as ........
    • A. 

      Minimum on state current required to keep the device in the on state after the triggering pulse has been removed SCR will not Turn off

    • B. 

      Minimum on state current required to keep the device in the on state after the triggering pulse has been removed SCR will remain Turn ON

    • C. 

      Minimum on state current required to keep the device in the on state after the triggering pulse has been removed SCR will  Turn off

    • D. 

      Both 1 & 2

  • 2. 
    Holding current define as .......
    • A. 

      It is mimimum forward anode current required to keep SCR on if the current fall below the holding level,then SCR remain in  turn on

    • B. 

      It is mimimum forward anode current required to keep SCR on if the current fall below the holding level,then SCR   turn off

    • C. 

      Both 1 &  2

    • D. 

      None of above

  • 3. 
                      I=    α2Ig+IcEo   /   (1-α)   in this equation if α approaches to unity then anode current will be
    • A. 

      Zero

    • B. 

      Minimum

    • C. 

      Increases

    • D. 

      None of above

  • 4. 
    If value of latching current is 12mA what is the value of holding current.....
    • A. 

      10mA

    • B. 

      13mA

    • C. 

      14mA

    • D. 

      15mA

  • 5. 
    For 4000V,3000A GTO need .........gate current to Turn Off
    • A. 

      750A

    • B. 

      -750A

    • C. 

      780A

    • D. 

      -780A

  • 6. 
    In TRIAC which mode is less sensitive
    • A. 

      Mode I & II

    • B. 

      Mode II & III

    • C. 

      Mode I & IV

    • D. 

      Mode III & IV

  • 7. 
    Arrow in the MOSFET symbol indicates..........
    • A. 

      Direction of Hole flow

    • B. 

      Dirction of Current flow

    • C. 

      Direction of electron flow

    • D. 

      All of the above 

  • 8. 
    Power MOSFET is .....
    • A. 

      Voltage control Device

    • B. 

      Current control Device

    • C. 

      Both 1 & 2

    • D. 

      None of above

  • 9. 
    In IGBT three terminals are .....
    • A. 

      Drain ,source & Gate

    • B. 

      Collector,Emitter & Gate

    • C. 

      Drain,Source& Emitter

    • D. 

      Both 1 & 2

  • 10. 
    In which condition IGBT Turn on
    • A. 

      VGS>VGS(TH)

    • B. 

      VGS

    • C. 

      VGS=VGS(TH)

    • D. 

      VGS=0

  • 11. 
    Interbase resistance (RBB) in UJT exist between.....
    • A. 

      3K Ohm to 4K Ohm

    • B. 

      1K Ohm to 3k Ohm

    • C. 

      4K Ohm to 10k Ohm

    • D. 

      10K Ohm to 14k Ohm

  • 12. 
    Intrinsic stand off ratio range in between .....
    • A. 

      0.2 to 0.4

    • B. 

      0.3 to 0.5

    • C. 

      0.9 to 1.3

    • D. 

      0.5 to 0.8

  • 13. 
    Which device is called as uncontrolled rectifier
    • A. 

      SCR

    • B. 

      Diode

    • C. 

      BJT

    • D. 

      PUT

  • 14. 
    In 2 quadrant converter polarity of output voltage can be either  positive of negative however output current has one polarity only called as.......
    • A. 

      Full converter

    • B. 

      Semiconverter

    • C. 

      Dual Converter

    • D. 

      Both 1& 2

  • 15. 
    Which one is not function of freewheeling diode......
    • A. 

      It prevent reversal of load voltage except for small voltage drop

    • B. 

      It convert AC to pulsating DC

    • C. 

      It transfer the load current away from the main rectifier,thereby allowing all of its thyristor to regain their blocking state

    • D. 

      None of above

  • 16. 
    In three phase half wave controlled rectifier with resistive load primary is.....
    • A. 

      Star connection

    • B. 

      Transformer connection

    • C. 

      Delta connection

    • D. 

      Both 1 & 3

  • 17. 
    In 3 phase half wave controlled rectifier conduction period for each thyristor is equal to ....
    • A. 

      60 degree

    • B. 

      80 degree

    • C. 

      100 degree

    • D. 

      120 degree

  • 18. 
    If dc circuit of 240V is to be protected with 25V selenium cell then how many cells required
    • A. 

      10

    • B. 

      12

    • C. 

      14

    • D. 

      16

  • 19. 
    For Thyristor overcurrent protection which is better option
    • A. 

      Selenium diode protection 

    • B. 

      Snubber circuit protection

    • C. 

      Crowbar protection

    • D. 

      Metal oxide varistor

  • 20. 
    How to turn off SCS
    • A. 

      Reduce anode current below IH

    • B. 

      By applying negative gate pulse to GK 

    • C. 

      By applying positive gate pulse to GA

    • D. 

      All of the above

  • 21. 
    Which device is complementry SCR
    • A. 

      SUS

    • B. 

      SBS

    • C. 

      LASCR

    • D. 

      PUT

  • 22. 
    Which method is more reliable  & efficient to turn ON SCR
    • A. 

      Forward voltage triggering

    • B. 

      Gate triggering

    • C. 

      Dv/dt triggering

    • D. 

      Thermal triggering

  • 23. 
    Reverse characteristics of SCR similer to the...
    • A. 

      TRIAC

    • B. 

      DIAC

    • C. 

      Diode

    • D. 

      UJT

  • 24. 
    Device used for a chopper can be represented by
    • A. 

      Circle

    • B. 

      Square block

    • C. 

      Switch with an arrow

    • D. 

      Zig-zac

  • 25. 
    In light Dimmer if Pot is in mid position then intensity of light is 
    • A. 

      Medium intensity

    • B. 

      Low intensity

    • C. 

      High intensity

    • D. 

      Bulb in off condition

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