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  • Question

  • In a 3 phase semiconverter, the firing frequency is


  • Options
  • A. equal to line frequency
  • B. 3 times the line frequency
  • C. 6 times the line frequency
  • D. 12 times the line frequency

  • Correct Answer
  • 3 times the line frequency 

    Explanation
    Since the circuit has 3 thyristors, firing frequency is three times the line frequency.

    More questions

    • 1. Consider a 300 ?, quarter wave long at 1 GHz transmission line as shown in figure. It is connected to a 10 V, 50 ? source at one end is left open circuited at the other end. The magnitude of the voltage at the open circuit end of the line is

    • Options
    • A. 10 V
    • B. 5 V
    • C. 60 V
    • D. 60/7 volt
      • Discuss
    • 2. The image frequency of a superheterodyne receiver is

    • Options
    • A. independent of the frequency at which the receiver is tuned
    • B. always outside the operating range of the receiver
    • C. typical to FM receivers only
    • D. not rejected by the IF tuned circuits
      • Discuss
    • 3. If a metal specimen has n valence electrons per m3 each having charge e and mass m and t is the relaxations time, the conductivity is

    • Options
    • A.
    • B.
    • C.
    • D.
      • Discuss
    • 4. The v-i characteristic shown in the given figure is for

    • Options
    • A. thermistor
    • B. photoconductor
    • C. varistor
    • D. none of the above
      • Discuss
    • 5. Fleming's left hand rule is used to find

    • Options
    • A. direction of force on a current carrying conductor
    • B. direction of flux in solenoid
    • C. direction of magnetic field due to a current carrying conductor
    • D. direction of induced emf
      • Discuss
    • 6. Consider the following materials

      1. Nickel
      2. Silver
      3. Oxygen
      4. Aluminium
      The correct sequence in the order of decreasing permeability is

    • Options
    • A. 1, 4, 3, 2
    • B. 1, 4, 2, 3
    • C. 4, 1, 3, 2
    • D. 4, 1, 2, 3
      • Discuss
    • 7. In a full bridge inverter, the waveshape of load current depends on

    • Options
    • A. relative values of load parameters R, L and C
    • B. relative values of load parameters R and L
    • C. relative values of load parameters L and C
    • D. gating frequency
      • Discuss
    • 8. In the basic series inverter circuit, the source supplies load

    • Options
    • A. only in positive half cycle
    • B. both in positive and negative half cycles
    • C. only in part of positive half cycle
    • D. in positive half cycle and part of negative half cycle
      • Discuss
    • 9. In rectifier circuits, ripple factor RF and form factor FF are related as

    • Options
    • A. RF = (FF2 - 1)0.5
    • B. RF = FF
    • C. RF = FF - 1
    • D. RF = (FF - 1)0.5
      • Discuss
    • 10. In a radio receiver

    • Options
    • A. the local oscillator frequency is made higher than the incoming signal frequency
    • B. the local oscillator frequency is made lower than the incoming signal frequency
    • C. the local oscillator frequency is made equal to the incoming signal frequency
      • Discuss

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