FETs, MOSFETs

Field-effect transistors (FET) are electronic devices which use an electric field to control the flow of current. Application of a voltage to the gate terminal alters the conductivity between the drain and source terminals. FETs are also known as unipolar transistors since they involve single-carrier-type operation. That is, FETs use electrons or holes as charge carriers in their operation, but not both. Field effect transistors generally display very high input impedance at low frequencies. Metal oxide semiconductor field effect transistors, or MOSFETs, are a type of FET.