What is the main function of a voltage follower using an operational amplifier?

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To amplify the input signal

To provide high input impedance and low output impedance

To invert the input signal

To filter out noise from the signal

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Answer

A voltage follower, also called a unity‑gain buffer, uses an op‑amp to copy an input voltage exactly to its output without changing it. The op‑amp’s negative feedback forces the output to equal the input, so the gain is one. Because the input is connected to the op‑amp’s inverting terminal and the output feeds back to that same terminal, the circuit presents a very high input impedance and a very low output impedance, making it ideal for driving loads. For example, if you connect a 3 V source to the input, the output will also be 3 V while the source sees almost no load. This makes the voltage follower perfect for isolating a signal source from a heavy load.

Detailed Explanation

A voltage follower gives the circuit a very high input impedance so it does not load the source. Other options are incorrect because It is easy to think a buffer makes the signal bigger, but the voltage follower actually keeps the voltage exactly the same; Some people mix up the follower with the inverting amplifier.

Key Concepts

voltage follower

Topic

Operational Amplifiers Basics

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easy level question

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understand

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