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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   