The gain of an amplifier without feedback is 100 db. If a negative feedback of 3 db is applied, the gain of the amplifier will become ___________

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

A

$$\frac{1}{{11}}{\text{k}}\Omega $$

B

$$\frac{1}{5}{\text{k}}\Omega $$

C

5 kΩ

D

11 kΩ

A system has a gain of 80 db without feedback, if the negative feedback is 1/50th. What is the closed loop gain of the system in db with the addition of the negative feedback?

A

34db

B

40db

C

30db

D

42db

An amplifier of gain 1000 is made into a feedback amplifier by feeding 9.9% of its output voltage in series with the input opposing. If f_L = 20 Hz and f_H = 200 kHz for the amplifier without feedback, then due to the feedback

A

the gain decreases by 10 times

B

the output resistance increases by 10 times

C

the f_H increases by 100 times

D

the input resistance decreases by 100 times

Consider the following statements with respect to the feedback from the control systems: 1. The feedback can improve stability or be harmful to stability if it is not properly applied. 2. The feedback can always improve stability. 3. In many situations, the feedback can reduce the effect of noise and disturbance on system performance. 4. In general, the sensitivity of the system gain of a feedback system of a parameter variation depends on where the parameter is located. Select the correct statements.

A

1, 2 and 3 only

B

1, 2 and 4 only

C

1, 3 and 4 only

D

1, 2, 3, and 4

Consider the following statements with respect to the feedback of the control systems. i. Feedback can improve stability or be harmful to stability if it is not properly applied. ii. Feedback can always improve stability iii. In many situations the feedback can reduce the effect of noise and disturbance on system performance. iv. In general the sensitivity of the system gain of a feedback system of a parameter variation depends on where the parameter is located.

A

i, ii, iii and iv only

B

i, ii and iii only

C

i, iii and iv only

D

i, ii and iv only

Consider the following statements with respect to the feedback of the control systems: 1. Feedback can improve stability or be harmful to stability if it is not properly applied. 2. Feedback can always improve stability 3. In many situations the feedback can reduce the effect of noise and disturbance on system performance. 4. In general the sensitivity of the system gain of a feedback system of a parameter variation depends on where the parameter is located.

A

1,2 and 3 only

B

1,3 and 4 only

C

1,2 and 4 only

D

1,2,3 and 4 only

For an RC phase shift oscillator, the following statements are cited: a) Amplifier gain is negative b) Phase shift introduced by the feedback circuit is either 0 or 360° c) Amplifier gain is positive d) Phase shift introduced by the feedback circuit is 180° Which of the following options is correct?

A

Only a) is correct and rest are incorrect

B

Only c) is correct and rest are incorrect

C

Both a) and d) are correct

D

Both b) and c) are correct

Assertion (A): A linear, negative feedback control system is invariable stable if its open loop configuration is stable Reason (R): the negative feedback reduces the overall gain of the feedback.

A

Both A and R are true and R is correct explanation of A

B

Both A and R are true and R is not correct Explanation of A

C

A is True and R is false

D

A is False and R is true

The feedback ratio of an amplifier, which on application of a negative feedback, changes the voltage gain from -250 to -100 is

A

-0.250

B

-0.025

C

-0.060

D

-0.006

Specify the voltage gain of non-inverting amplifier with feedback amplifier with and without feedback?

A

A= Vo/Vid, AF = Vf/Vo

B

A= Vf/Vid, AF= Vo/Vf

C

A= Vo/Vid, AF= Vo/Vin

D

A= Vf/Vid, AF = Vf/Vin

The gain of an amplifier without feedback is 100 db. If a negative feedback of 3 db is applied, the gain of the amplifier will become ___________

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