An amplifier without feedback has a voltage gain of 50,input resistance os 1 KΩ & Output resistance of 2.5KΩ.The input resistance of the current-shunt negative feedback amplifier using the above amplifier with a feedback factor of 0.2 is___________?

Related Mcqs:

1. 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_________?

   A. 49dB
   B. 51dB
   C. 98dB
   D. 102dB

2. An amplifier using an opamp with slew rate SR=1v/µsec has a gain of 40db.if this amplifier has to faithfully amplify sinusoidal signals from dc to 20 KHz without introducing any slew-rate induced distortion, then the input signal level must not exceed________?

   A. 795mV
   B. 395mV
   C. 795 mV
   D. 39.5mV

3. Voltage Series feedback also called series-shunt feedback) results in__________?

   A. Increase in both input & output impedances
   B. Decreases in both input & output impedances
   C. Increase in input impedance & decreases in output impedance
   D. Decrease in input impedance & increase in output impedance

4. In the differential voltage gain & the common mode voltage gain of a differential amplifier are 48db &2db respectively, then its common mode rejection ratio is__________?

   A. 23dB
   B. 25dB
   C. 46dB
   D. 50dB

5. A 741-type OP-AMP has a gain-bandwidth product of 1MHz. A non-inverting amplifier using this op-amp & having a voltage gain of 20db will exhibit -3db bandwidth of__________?

   A. 50 KHz
   B. 100KHz
   C. 1000/17 KHz
   D. 1000/7.07 KHz

6. 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_____________?

   A. 5 Ω & 20 %
   B. 25 Ω & 20 %
   C. 5 Ω & 16.7 %
   D. 25 Ω & 16.7 %

7. A differential amplifier has a differential gain of 20,000 . CMRR=80 dB. The common mode gain is given by________?

   A. 2
   B. 1
   C. 1/2
   D. 0

8. A source follower using an FET usually has a voltage gain which is___________?

   A. greater than +100
   B. slightly less than unity but positive
   C. exactly unity but negative
   D. about -10

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.

   A. 10 volts
   B. 5 volts
   C. 5/1 volts
   D. 5/2 volts

10. Negative feedback in an amplifier____________?

    A. Reduces gain
    B. Increase frequency &phase distortion
    C. Reduces bandwidth
    D. Increases noise