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EEE :: Transistor Audio Power Amplifiers

  1. A class A power amplifier uses ___________

  2. A.

     Two transistors

    B.

     Three transistors

    C.

     One transistor

    D.

     None of the above


  3. The maximum efficiency of transformer coupled class A power amplifier is ___________

  4. A.

     30%

    B.

     50%

    C.

     80%

    D.

     45%


  5. The most important consideration in power amplifier is ___________

  6. A.

     Biasing the circuit

    B.

     Collector efficiency

    C.

     To keep the transformer cool

    D.

     None of the above


  7. What turn ratio (Np/Ns) of transformer is required to match 4 Ω speaker to a transistor having an output impedance of 8000 O?

  8. A.

     2

    B.

     7

    C.

     3

    D.

     None of the above


  9. The size of a power transistor is made considerably large to ___________

  10. A.

     Provide easy handling

    B.

     Dissipate heat

    C.

     Facilitate connections

    D.

     None of the above


  11. If the power rating of a transistor is 1W and collector current is 100mA, then maximum allowable collector voltage is ___________

  12. A.

     1V

    B.

     100V

    C.

     20V

    D.

     10V


  13. The output stage of a multistage amplifier is also called ___________

  14. A.

     Mixer stage

    B.

     Power stage

    C.

     Detector stage

    D.

     F stage


  15. Power amplifiers handle ___________ signals compare to voltage amplifiers

  16. A.

     Small

    B.

     Very small

    C.

     Large

    D.

     None of the above


  17. The pulsating d.c. applied to power amplifier causes ___________

  18. A.

     Burning of transistor

    B.

     Hum in the circuit

    C.

     Excessive forward voltage

    D.

     None of the above


  19. For the same a.c. power output as above, what should be the minimum power rating of transistor for class B operation?

  20. A.

     10 W

    B.

     4 W

    C.

     8 W

    D.

     None of the above