A MOSFET, or Metal-Oxide-Semiconductor Field-Effect Transistor, is a type of transistor used to amplify or switch electronic signals. It has three terminals: gate, drain, and source. The gate controls the flow of current between the drain and source, allowing for efficient control of electrical power in circuits. MOSFETs are widely used in various applications, including computers, power supplies, and motor controllers. They are favored for their high efficiency and fast switching speeds, making them essential components in modern electronic devices. Their ability to handle high voltages and currents also contributes to their popularity in power electronics.