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Home ‣ Electronics and Communication Engineering ‣ Microwave Communication See What Others Are Saying!
  • Question

  • A magnetron has a cylindrical cathode surrounded by an anode structure having cavities opening into interaction space by means of slots


  • Options
  • A. True
  • B. False

  • Correct Answer
  • True 

    Explanation
    It is somewhat similar to TWT and can deliver microwave power over a wide frequency band.

    It has an electron gun and a helix structure. However the interaction between electron beam and RF wave is different than in TWT.

    The growing RF wave travels in opposite direction to the electron beam.

    The frequency of wave can be changed by changing the voltage which controls the beam velocity.

    Moreover the amplitude of oscillations can be decreased continuously to zero by changing the beam current.

    It features are:

    1. Frequency range - 1 GHz to 1000 GHz.

    2. Power output - 10 mV to 150 mW (continuous wave) 250kW (pulsed).

    It is used as signal source in transmitters and instruments.

    More questions

    • 1. Match the following:

      List I (VCR system) List II (Azimuth angle)
      A. VHS 1. 7°
      B. Video 2000 2. 15°
      C. Betamax 3. 6°


    • Options
    • A. A-1, B-2, C-3
    • B. A-1, B-3, C-2
    • C. A-3, B-1, C-2
    • D. A-3, B-2, C-1
      • Discuss
    • 2. Match the following:

      List I List II
      A. Copper 1. produces discrete energy level just above valence band
      B. Rubber 2. produces discrete energy level just below conduction band
      C. Antimony 3. large forbidden gap
      D. Boron 4. valence and conduction bands overlap


    • Options
    • A. A-1, B-2, C-4, D-3
    • B. A-4, B-1, C-2, D-3
    • C. A-4, B-3, C-1, D-2
    • D. A-2, B-1, C-3, D-4
      • Discuss
    • 3. The number of doped regions in a SCR is

    • Options
    • A. 2
    • B. 3
    • C. 4
    • D. 5
      • Discuss
    • 4. In a half bridge inverter the gate pulses of the two thyristors have a phase displacement of

    • Options
    • A. 60°
    • B. 90°
    • C. 120°
    • D. 180°
      • Discuss
    • 5. A loss less line of characteristic impedance Z0 is terminated in pure reactance of -jZ0 value. VSWR is

    • Options
    • A. 10
    • B. 2
    • C. 1
    • D. infinity
      • Discuss
    • 6. A typical error rate on satellite circuits is one bit error in

    • Options
    • A. 107
    • B. 103
    • C. 102
    • D. 1010
      • Discuss
    • 7. In elemental dielectrics, the orientation and ionic polarization are absent.

    • Options
    • A. True
    • B. False
      • Discuss
    • 8. Which of the following should be used in order to prevent overloading or the last IF amplifier in a receiver?

    • Options
    • A. Variable selectivity
    • B. Variable sensitivity
    • C. Double conversion
    • D. Squelch
      • Discuss
    • 9. The waveshape of output voltage of half bridge inverter is

    • Options
    • A. sinusoidal
    • B. square
    • C. triangular
    • D. either (a) or (b)
      • Discuss
    • 10. The main utility of SCR is due to

    • Options
    • A. gate triggering
    • B. high temperature triggering
    • C. triggering
    • D. high breakdown voltage
      • Discuss

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