logo

CuriousTab

CuriousTab

Discussion

Home ‣ Electronics and Communication Engineering ‣ Microwave Communication Comments
  • Question

  • In a reflex klystron oscillator, repeller electrode is at


  • Options
  • A. low positive potential
  • B. high positive potential
  • C. negative potential
  • D. zero potential

  • Correct Answer
  • negative potential 

    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.

    Microwave Communication problems

    Search Results

    • 1. In high frequency circuits impedance matching can be done by

      1. open circuited stubs
      2. short circuited stubs
      3. transformer
      Which of the above correct?

    • Options
    • A. 1, 2 and 3
    • B. 1 and 2 only
    • C. 1 and 3 only
    • D. 2 and 3 only
      • Discuss
    • 2. Assertion (A): Gate triggering is the most commonly used method for triggering of an SCR.

      Reason (R): Even a small gate current is sufficient to turn on an SCR.


    • 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
    • 3. In an n stage high frequency series inverter having a time period T, each stage is active for a time interval of

    • Options
    • A. T
    • B.
    • C.
    • D.
      • Discuss
    • 4. McMurrary full bridge inverter uses

    • Options
    • A. auxiliary commutation
    • B. complementary commutation
    • C. natural commutation
    • D. any of the above
      • Discuss
    • 5. In a semi converter feeding a resistive load

    • Options
    • A. the waveshapes of output voltage and output current are exactly similar
    • B. the waveshapes of output voltage and output current can not be similar
    • C. the waveshapes of output voltage and output current are similar only for low values of firing angle
    • D. the waveshapes of output voltage and output current may be similar or dissimilar
      • Discuss
    • 6. Assertion (A): A backward wave oscillator can be used as a sweep generator.

      Reason (R): The frequency of oscillation of a backward wave oscillator can be changed by varying the voltage which controls the beam velocity.


    • Options
    • A. Both A and R are correct and R is correct explanation of A
    • B. Both A and R are 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
    • 7. Assertion (A): PIN diode is commonly used for microwave control.

      Reason (R): A PIN diode uses heavily doped p and n materials.


    • Options
    • A. Both A and R are correct and R is correct explanation of A
    • B. Both A and R are 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. Assertion (A): The velocity factor of a line is the ratio of wave velocity on the line to speed of light.

      Reason (R): If the conductors of a line are immersed in a non magnetic insulating liquid, the wave velocity increases.


    • Options
    • A. Both A and R are correct and R is correct explanation of A
    • B. Both A and R are 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
    • 9. The magnitudes of OC and SC input impedances of a transmission line an 100 ? and 25 ?. The characteristic impedance is

    • Options
    • A. 25 ?
    • B. 50 ?
    • C. 75 ?
    • D. 100 ?
      • Discuss
    • 10. Assertion (A): A quarter wave transformer is used to match a resistive load to a transmission line.

      Reason (R): A quarter wave transformer is a transmission line of quarter wave length.


    • Options
    • A. Both A and R are correct and R is correct explanation of A
    • B. Both A and R are 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

    Comments

    There are no comments.
Enter a new Comment




Aptitude

Engineering

Programming

Reasoning

Links

Copyright ©CuriousTab. All rights reserved.