A MOSFET amplifier is an electronic device that uses a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) to amplify electrical signals. It operates by controlling the flow of current through the transistor, allowing small input signals to produce larger output signals. This makes it useful in various applications, including audio equipment and radio frequency devices. MOSFET amplifiers are known for their high input impedance and low output impedance, which helps minimize signal loss. They can be configured in different ways, such as common source or common drain, to achieve desired amplification characteristics. Their efficiency and performance make them popular in modern electronic circuits.