The correct answer is (b) Voltage follower.
Here’s why:
A non-inverting amplifier with feedback has a configuration where the input signal is applied to the non-inverting input of the operational amplifier (op-amp). The output is in phase with the input, and the voltage gain is greater than or equal to 1. When the feedback is designed to make the gain exactly equal to 1, this configuration is referred to as a voltage follower or buffer amplifier.
A voltage follower (also called a unity-gain amplifier) provides the same voltage at the output as the input, with no amplification (gain = 1), which essentially mirrors the behavior of a non-inverting amplifier with feedback when the gain is set to 1.
Let's review the options:
(a) Perfect feedback amplifier: This is a more general term and doesn’t specifically imply unity gain, so it doesn’t exactly match the non-inverting amplifier with feedback in this context.
(b) Voltage follower: This is correct. It has the same characteristic as a non-inverting amplifier with feedback when the feedback ensures a unity gain (i.e., the output equals the input).
(c) Perfect voltage amplifier: This generally refers to an amplifier with very high gain, which isn’t necessarily the same as a non-inverting amplifier with feedback (especially at unity gain).
(d) All of the mentioned: Since not all the options are correct, this is not the correct choice.
Thus, the correct answer is (b) Voltage follower.