Gibilisco - Power Supplies

20 Questions | Total Attempts: 817

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Power Quizzes & Trivia

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Questions and Answers
  • 1. 
    The output of a rectifier circuit without a filter included is
    • A. 

      60 Hz ac.

    • B. 

      Smooth dc.

    • C. 

      Pulsating dc.

    • D. 

      120 Hz ac.

  • 2. 
    • A. 

      The transformer

    • B. 

      The filter

    • C. 

      The rectifier

    • D. 

      All of the above components are required.

  • 3. 
    Of the following appliances, which would need the biggest transformer?
    • A. 

      A clock radio

    • B. 

      A television broadcast transmitter

    • C. 

      A shortwave radio receiver

    • D. 

      A home television set

  • 4. 
    An advantage of full-wave bridge rectification is the fact that
    • A. 

      It uses the whole transformer secondary for the entire ac input cycle.

    • B. 

      It costs less than other rectifier types.

    • C. 

      It cuts off half of the ac wave cycle.

    • D. 

      It never needs a filter.

  • 5. 
    In a power supply designed to provide high power at low voltage, the best rectifier circuitwould probably be the
    • A. 

      Half-wave arrangement.

    • B. 

      Full-wave, center-tap arrangement.

    • C. 

      Quarter-wave arrangement.

    • D. 

      Voltage doubler arrangement.

  • 6. 
    The part of a power supply immediately preceding the regulator is
    • A. 

      The transformer.

    • B. 

      The rectifier.

    • C. 

      The filter.

    • D. 

      The ac input.

  • 7. 
    If a half-wave rectifier is used with 165-V pk ac input, the effective dc output voltage is
    • A. 

      Considerably less than 165 V.

    • B. 

      Slightly less than 165 V.

    • C. 

      Exactly 165 V.

    • D. 

      Slightly more than 165 V.

  • 8. 
    If a full-wave bridge circuit is used with a transformer whose secondary provides 50 V rms,the peak voltage that occurs across the diodes in the reverse direction is approximately
    • A. 

      50 V pk.

    • B. 

      70 V pk.

    • C. 

      100 V pk.

    • D. 

      140 V pk.

  • 9. 
    What is the principal disadvantage of a voltage-doubler power supply circuit?
    • A. 

      Excessive current

    • B. 

      Excessive voltage

    • C. 

      Insufficient rectification

    • D. 

      Poor regulation under heavy loads

  • 10. 
    Suppose a transformer secondary provides 10-V rms ac to a voltage-doubler circuit. What isthe approximate dc output voltage with no load?
    • A. 

      14 V

    • B. 

      20 V

    • C. 

      28 V

    • D. 

      36 V

  • 11. 
    The ripple frequency from a full-wave rectifier is
    • A. 

      Twice that from a half-wave circuit.

    • B. 

      The same as that from a half-wave circuit.

    • C. 

      Half that from a half-wave circuit.

    • D. 

      1⁄4 that from a half-wave circuit.

  • 12. 
    Which of the following would make the best filter for a power supply?
    • A. 

      A capacitor in series

    • B. 

      A choke in series

    • C. 

      A capacitor in series and a choke in parallel

    • D. 

      A capacitor in parallel and a choke in series

  • 13. 
    Voltage regulation can be accomplished by a Zener diode connected in
    • A. 

      Parallel with the filter output, forward-biased.

    • B. 

      Parallel with the filter output, reverse-biased.

    • C. 

      Series with the filter output, forward-biased.

    • D. 

      Series with the filter output, reverse-biased.

  • 14. 
    A current surge takes place when a power supply is first turned on because
    • A. 

      The transformer core is suddenly magnetized.

    • B. 

      The diodes suddenly start to conduct.

    • C. 

      The filter capacitor(s) must be initially charged.

    • D. 

      Arcing takes place in the power switch.

  • 15. 
    Transient suppression is of importance mainly because it minimizes the risk of
    • A. 

      Diode failure.

    • B. 

      Transformer imbalance.

    • C. 

      Filter capacitor overcharging.

    • D. 

      Poor voltage regulation.

  • 16. 
    Suppose you see a fuse with nothing but a straight wire inside. You can assume that this fuse
    • A. 

      Is a slow-blow type.

    • B. 

      Is a quick-break type.

    • C. 

      Has a low current rating.

    • D. 

      Has a high current rating.

  • 17. 
    In order to minimize the risk of diode destruction as a result of surge currents that can occurwhen a power supply is first switched on, which of the following techniques can be useful?
    • A. 

      Connecting multiple diodes in parallel, with low-value resistors in series with each diode

    • B. 

      Connecting multiple diodes in parallel, with low-value capacitors in series with each diode

    • C. 

      Connecting multiple diodes in series, with low-value chokes across each diode

    • D. 

      Connecting multiple diodes in series, with low-value resistors across each diode

  • 18. 
    To repair a damaged power supply with which you are not completely familiar, you should
    • A. 

      Install bleeder resistors before beginning your work.

    • B. 

      Remove the fuse before beginning your work.

    • C. 

      Leave it alone and have a professional work on it.

    • D. 

      Short out all the diodes before beginning your work.

  • 19. 
    If a fuse blows, and it is replaced with one having a lower current rating, there is a goodchance that
    • A. 

      The power supply will be severely damaged.

    • B. 

      The diodes will not rectify.

    • C. 

      The fuse will blow out right away.

    • D. 

      Transient suppressors won’t work.

  • 20. 
    If you need exceptionally good ripple filtering for a power supply, which of the followingalternatives will yield the best results?
    • A. 

      Connect several capacitors in parallel.

    • B. 

      Use a choke-input filter.

    • C. 

      Connect several chokes in series.

    • D. 

      Use two capacitor/choke filtering sections in cascade.