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EEE :: OP amp

  1. The common mode gain is ___________

  2. A.

     very high

    B.

     very low

    C.

     always unity

    D.

     unpredictable


  3. An amplifier using an opamp with slew rate SR=1v/sec has a gain of 40db.If this amplifier has to faithfully amplify sinusoidal signals from dc to 20KHz without introducing any slew-rate induced distortion, then the input signal level exceed

  4. A.

     795mV

    B.

     395mV

    C.

     795mV

    D.

     39.5mV


  5. Current cannot flow to ground through .

  6. A.

     a mechanical ground

    B.

     an a.c. ground

    C.

     a virtual ground

    D.

     an ordinary ground


  7. When a step-input is given to an OP-amp integrator, the output will be

  8. A.

     A ramp

    B.

     A sinusoidal wave

    C.

     A rectangular wave

    D.

     A triangular wave with dc bias


  9. An OPAMP has a slew rate of 5 V/μ S .The largest sine wave O/P voltage possible at a frequency of 1 MHZ is
    [Hint: Slew rate is defined as the max. rate of change of output voltage. Its unit is V/μS.]

  10. A.

     10 volts

    B.

     5 volts

    C.

     5/1 volts

    D.

     5/2 volts


  11. Calculate the cutoff frequency of a first-order low-pass filter for R1 = 2.5kΩ and C1 = 0.05μF

  12. A.

     1.273 kHz

    B.

     12.73 kHz

    C.

     127.3 kHz

    D.

     127.3 Hz


  13. The output of a particular OP-amp increases 8V in 12µs. The slew rate is

  14. A.

     90 V/µs

    B.

     0.67 V/µs

    C.

     1.5 V/µs

    D.

     none of these


  15. The approximate input impedance of the opamp circuit which has Ri=10k, Rf=100k, RL=10k

  16. A.

     ∞

    B.

     120k

    C.

     110k

    D.

     10k


  17. For an OP-amp with negative feedback, the output is .

  18. A.

     equal to the input

    B.

     increased

    C.

     fed back to the inverting input

    D.

     fed back to the noninverting input


  19. The common mode voltage gain of a differential amplifier is equal to RC divided by

  20. A.

     re

    B.

     2re

    C.

     re/2

    D.

     2RE