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  • Question

  • Which of the following devices has metal-silicon junction?


  • Options
  • A. General purpose power diode
  • B. Schottky diode
  • C. SCR
  • D. MOSFET

  • Correct Answer
  • Schottky diode 

    • Power Electronics problems

    Search Results

    • 1. In a single phase full wave ac regulator using two thyristors only, the gate circuits of the two thyristors

    • Options
    • A. must be isolated
    • B. may or may not be isolated
    • C. should be preferably, isolated
    • D. should not be isolated
      • Discuss
    • 2. When a dc chopper feeds an RLE load, the load current, during steady state operation

    • Options
    • A. remains constant
    • B. varies between maximum and minimum values
    • C. may remain constant or vary
    • D. is constant if R is constant
      • Discuss
    • 3. A single phase half bridge inverter required to feed R-L loads needs

    • Options
    • A. 2 thyristors
    • B. 4 thyristors
    • C. 2 thyristors and two diodes
    • D. 4 thyristors and 4 diodes
      • Discuss
    • 4. HVDC systems are preferable for only long distances.

    • Options
    • A. True
    • B. False
      • Discuss
    • 5. In a single phase half wave converter feeding resistive load and full wave converter (M - 2 connection) feeding a resistive load the circuit conditions are similar. The firing angle is a. Then the waveshapes of voltages across thyristors

    • Options
    • A. are similar
    • B. are not similar
    • C. may be similar or dissimilar
    • D. are similar only for some values of a
      • Discuss
    • 6. The main utility of SCR is due to

    • Options
    • A. gate triggering
    • B. high temperature triggering
    • C. triggering
    • D. high breakdown voltage
      • Discuss
    • 7. Assertion (A): A half wave controlled rectifier has poorer efficiency and higher ripple factor than a full wave controlled rectifier.

      Reason (R): The use of a freewheeling diode in half wave controlled rectifier circuit improves the waveform of load current and circuit power factor.


    • Options
    • A. Both A and R are correct and R is correct explanation of A
    • B. Both A and R correct but R is not correct explanation of A
    • C. A is correct but R is wrong
    • D. A is wrong but R is correct
      • Discuss
    • 8. A fully controlled bridge converter is feeding an RLE load. For some circuit conditions firing angle is 47°. If connections of battery are reversed, the firing angle is likely to be

    • Options
    • A. 47°
    • B. less than 47°
    • C. more than 47°
    • D. either more or less than 47°
      • Discuss
    • 9. The efficiency of a chopper circuit is about

    • Options
    • A. 80% or more
    • B. around 50%
    • C. around 20%
    • D. around 5%
      • Discuss
    • 10. Which of these devices can conduct in both directions?

    • Options
    • A. SCR
    • B. SUS
    • C. SBS
    • D. UJT
      • Discuss

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