MOSFET stands for Metal-Oxide-Semiconductor Field-Effect Transistor.

It is a field-effect transistor with a MOS structure. Typically, the MOSFET is a three-terminal device with

• gate (G),
• drain (D) and
• source (S) terminals.

Current conduction between drain (D) and source (S) is controlled by the amount of voltage applied to the gate (G) terminal.

MOSFETs can be compare favorably with bipolar transistors in terms of relatively high-speed and low-loss operation. There are P type and N type channel polarity, and there are enhancement type with normally off (gate voltage 0 V off) and depletion type with normally on (deactivated with gate voltage 0 V) by control method.