field effect transistor A type of transistor, usually made of semiconductors, in which the flow of current from a source on one side to a drain on the other is regulated by the strength of an electric field. This field is produced by a voltage at a third point called the gate, which effectively squeezes or opens the channel to the flow of current. Field effect transistors are especially useful for amplifying or switching very low power signals, as found in portable wireless technology, microprocessors, and digital memory circuits. Compare bipolar transistor. |