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ECE :: Analog Electronics

  1. Asource follower using an FET usually has a voltage gain which is

  2. A.

     Greater than +100

    B.

     Slightly less than unity but positive

    C.

     Exactly unity but negative

    D.

     About -10


  3. Three identical amplifiers with each one having a voltage gain of 50,input resistance of 1KΩ & output resistance of 250, are cascaded. The open circuit voltage gain of combined amplifier is

  4. A.

     49dB

    B.

     51dB

    C.

     98dB

    D.

     102dB


  5. A dc power supply has no-load voltage of 30v,and a full-load voltage of 25v at full-load current of 1A.Its output resistance & load regulation ,respectively are

  6. A.

     5 Ω & 20 %

    B.

     25 Ω & 20 %

    C.

     5 Ω & 16.7 %

    D.

     25 Ω & 16.7 %


  7. In an OP-amp differentiator

  8. A.

     The amplitude of output is proportional to rate of change of input

    B.

     The amplitude of output is proportional to input

    C.

     Output occurs when input is finite and constant

    D.

     Polarity of input and output is the same


  9. Class AB operation is often used in power large signal) amplifiers in order to

  10. A.

     Get maximum efficiency

    B.

     Remove even harmonics

    C.

     Overcome a crossover distortion

    D.

     Reducing collector dissipation


  11. Which of the following amplifier circuit using junction transistor has the best gain?

  12. A.

     Common base

    B.

     Common emitter

    C.

     Common collector

    D.

     All have the same gain


  13. When a transistor is connected in common emitter mode, it with have

  14. A.

     Negligible input resistance and high output resistance

    B.

     High input resistance and low output resistance

    C.

     Medium input resistance and high output resistance

    D.

     Low input resistance as well as output resistance


  15. In all base driver amplifiers

  16. A.

     ac collector voltage is 180° out of phase with ac base voltage

    B.

     ac emitter voltage is 180° out of phase with ac base voltage

    C.

     ac collector voltage is in phase with ac base voltage

    D.

     none of the above


  17. The effective channel length of a MOSFET in a saturation decreases with increase in

  18. A.

     Gate voltage

    B.

     Drain voltage

    C.

     Source voltage

    D.

     Body voltage


  19. Which of the following statements is false?

  20. A.

     Push pull signals are equal and opposite in phase

    B.

     Class AB operation cannot be used for a push pull audio power output phase

    C.

     A push pull output transformer has a centre-tapped primary

    D.

     All of the above