What is source follower?

A source follower, also known as a common-source amplifier with a source output, is a type of transistor amplifier configuration, typically using a MOSFET, where the output is taken from the source terminal. It provides high input impedance, low output impedance, and unity voltage gain, making it ideal for impedance matching between circuits. The source follower is commonly used in applications such as buffering signals and driving loads without significant signal degradation. This configuration is valued for its ability to isolate different stages of a circuit while preserving signal integrity.