A Metal–Oxide–Semiconductor Field-Effect Transistor (MOSFET, MOS-FET, or MOS FET) is a field-effect transistor (FET with an insulated gate) where the voltage determines the conductivity of the device. It is used for switching or amplifying signals. The ability to change conductivity with the amount of applied voltage can be used for amplifying or switching electronic signals. MOSFETs are now even more common than BJTs (bipolar junction transistors) in digital and analog circuits. A Metal–Oxide–Semiconductor Field-Effect Transistor is by far the most common transistor in digital circuits, as hundreds of thousands or millions of them may be included in a memory chip or microprocessor.
E.g.: N-Channel Depletion mode MOS FET, P-Channel Depletion mode MOSFET, N-Channel Enhancement Mode MOS FET and P-Channel Enhancement mode MOS FET.