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  • Question

  • In colour TV receiver, varactor diode is used for


  • Options
  • A. detection
  • B. rectification
  • C. tuning
  • D. both (a) and (b)

  • Correct Answer
  • tuning 

    Explanation
    In varactor diode the applied reverse bias controls the width and therefore capacitance of depletion layer.

    This capacitance is used for tuning.

    More questions

    • 1. Which mode is called dominant mode in rectangular wave guide?

    • Options
    • A. TE01
    • B. TE11
    • C. TE10
    • D. TE20
      • Discuss
    • 2. A 3 phase fully controlled converter is a

    • Options
    • A. 3 pulse converter
    • B. 6 pulse converter
    • C. 2 pulse converter
    • D. 12 pulse converter
      • Discuss
    • 3. 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
    • 4. Some types of traps used in video IF amplifier of colour TV are

    • Options
    • A. shunt traps
    • B. series traps
    • C. absorption traps
    • D. all of the above
      • Discuss
    • 5. Which of the following devices exhibit negative resistance characteristics?

    • Options
    • A. UJT
    • B. PUT
    • C. Both UJT and PUT
    • D. UJT, PUT and SBS
      • Discuss
    • 6. In molecules of ionic crystals, orientation polarization is zero.

    • Options
    • A. True
    • B. False
      • Discuss
    • 7. Assertion (A): Magnetism can be explained by the theory of magnetic domains.

      Reason (R): The existence of magnetic domains is evident from the Bitter powder patterns.


    • 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
    • 8. Interference generated by electrical equipment and automobile ignition systems when observed closed to earth is

    • Options
    • A. horizontally polarized
    • B. vertically polarized
    • C. polarized both horizontally
    • D. not polarized
      • Discuss
    • 9. Frequency range for satellite communication is

    • Options
    • A. 1 kHz to 100 kHz
    • B. 100 kHz to 10 MHz
    • C. 10 MHz to 100 MHz
    • D. 1 GHz to 30 GHz
      • Discuss
    • 10. To prevent a DC return between source and load, it is necessary to use

    • Options
    • A. resistor between source and load
    • B. inductor between source and load
    • C. capacitor between source and load
    • D. either (a) or (b)
      • Discuss

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