Question

Negative feedback in amplifiers A. improves the signal-to-noise ratio at the input. B. improves the signal-to-noise ratio at the output. C. does not affect the signal-to-noise ratio at the output. D. reduces distortion. Choose the correct answer from the options given below:

• A. A, C and D only
• B. B, C and D only
• C. A and C only
• D. B and D only

Hint:

Remember the four key benefits of negative feedback: it stabilizes gain, increases bandwidth, reduces distortion, and modifies input/output impedances. Its effect on SNR is complex, but it does not generally improve the SNR of the incoming signal.

Answer 1

The Correct Option is A

Negative feedback in amplifiers has the following effects:

• A: Improves the signal-to-noise ratio at the input. Negative feedback typically reduces noise, thus improving the signal-to-noise ratio at the input.
• B: Improves the signal-to-noise ratio at the output. This is not always true. Negative feedback's impact on the output signal-to-noise ratio is not guaranteed to be positive.
• C: Does not affect the signal-to-noise ratio at the output. Negative feedback minimizes distortion and the sensitivity of the output signal-to-noise ratio to amplifier gain variations, but it doesn't drastically change it.
• D: Reduces distortion. Negative feedback is known to reduce distortion by improving amplifier linearity.

Conclusion:

The correct answer is: A, C, and D only.