Question

Voltage shunt feedback amplifier forms

(a) A negative feedback

(b) A positive feedback

(c) Both positive and negative

(d) None of the mentioned

I got this question in an international level competition.

This is a very interesting question from Voltage Shunt Feedback Amplifier topic in division Operational Amplifier Characteristics of Linear Integrated Circuits

Answer 1

The correct answer is:

(a) A negative feedback

Explanation:

A Voltage Shunt Feedback Amplifier typically involves negative feedback. Here's why:

• Negative Feedback: In a voltage shunt feedback amplifier, a portion of the output voltage is fed back to the inverting input of the op-amp. This negative feedback reduces the overall gain of the amplifier but improves its stability, bandwidth, and linearity. The feedback effectively forces the op-amp to adjust its output in a way that opposes any changes, stabilizing the system.

  In this configuration, the feedback is applied to the non-inverting input or inverting input (depending on the design), but it always works to reduce the gain by feeding the output back in such a way that it counters the input signal.

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Why the Other Options Are Incorrect:

• (b) Positive feedback: Positive feedback would lead to instability, oscillations, and potentially saturation. This is not the behavior of a typical voltage shunt feedback amplifier.
• (c) Both positive and negative feedback: A voltage shunt feedback amplifier specifically uses negative feedback, not both.
• (d) None of the mentioned: Since the correct answer is negative feedback, this option is incorrect.

Thus, a Voltage Shunt Feedback Amplifier always uses negative feedback to stabilize the gain and improve performance.