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  • Question

  • A klystron amplifier generally uses Pierce gun


  • Options
  • A. True
  • B. False

  • Correct Answer
  • True 

    Explanation
    It uses a single cavity resonator for generating microwave oscillations.

    Its parts are electron gun, resonator, repeller and output coupling.

    It operates on the principle of positive feed back.

    The repeller electrode is at negative potential and sends the partially bunched electron beam back to resonator cavity.

    This positive feedback supports oscillations. Its feature are:

    1. Frequency range - 2 to 100 GHz

    2. Power output - 10 MW to about 2 W

    3. Efficiency - 10 - 20 %

    Its applications include radar receivers, local oscillator in microwave devices, oscillator for microwave measurements in laboratories etc.

    More questions

    • 1. The power requirements of a DRAM in active and stand by modes is about

    • Options
    • A. 350 mW and 5 mW respectively
    • B. 350 mW each
    • C. 5 mW each
    • D. 350 mW and 100 mW respectively
      • Discuss
    • 2. The different access methods which permit many satellite users to operate in parallel through a single transponder without interfering with each other as

    • Options
    • A. Frequency Division Multiple Access (FDMA)
    • B. Time Division Multiple Access (TDMA)
    • C. Code Division Multiple Access (CDMA)
    • D. All of the above
      • Discuss
    • 3. Match the following:

      List I List II
      A. T (Reflection coefficient) = 0 1. (ZL - Zo)/(ZL + Zo)
      B. T = - 1 2. ZL = Zo
      C. T = + 1 3. ZL = 0
      D. - 1 < T < + 1 4. ZL = ?


    • Options
    • A. A-2, B-3, C-4, D-1
    • B. A-2, B-4, C-1, D-3
    • C. A-1, B-2, C-3, D-4
    • D. A-3, B-2, C-4, D-1
      • Discuss
    • 4. Assertion (A): Ferromagnetic materials possess ferromagnetic properties only when temperature is less than paramagnetic curie temperature.

      Reason (R): For a ferromagnetic material for T > ?f.


    • Options
    • A. Both A and R are true and R is correct explanation of A
    • B. Both A and R are true but R is not correct explanation of A
    • C. A is true but R is false
    • D. A is false but R is true
      • Discuss
    • 5. Bode magnitude plot is drawn between

    • Options
    • A. magnitude of network function and ?
    • B. dB magnitude and log ?
    • C. dB magnitude and ?
    • D. loge (magnitude) and log ?
      • Discuss
    • 6. A two branch parallel circuit has a 20 ? resistance and 1 H inductance in one branch and a 100 ?F capacitor in the second branch. It is fed from 100 V ac supply, at resonance, the input impedance of the circuit is

    • Options
    • A. 500 ?
    • B. 50 ?
    • C. 20 ?
    • D. 5 ?
      • Discuss
    • 7. The temperature coefficient of a thermistor

    • Options
    • A. is positive
    • B. is negative
    • C. zero
    • D. may be positive or negative depending on its composition
      • Discuss
    • 8. An amplifier has a large ac input signal. The clipping occurs on both the peaks. The output voltage will be nearly a

    • Options
    • A. sine wave
    • B. square wave
    • C. triangular wave
    • D. (a) or (c)
      • Discuss
    • 9. In the figure shown, A1, A2, A3 are identical Ammeters. If A1 and A3 read 5 and 13 A respectively, reading of A2 will be

    • Options
    • A. 8
    • B. 13 A
    • C. 18
    • D. 12 A
      • Discuss
    • 10. A relaxation oscillator uses

    • Options
    • A. tunnel diode
    • B. UJT
    • C. both tunnel diode and UJT
    • D. PIN diode
      • Discuss

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