Common gate

In electronics, a common-gateamplifier is one of three basic single-stage field-effect transistor (FET) amplifier topologies, typically used as a currentbuffer or voltageamplifier. In this circuit, the source terminal of the transistor serves as the input, the drain is the output, and the gate is connected to some DC biasing voltage (i.e. an AC ground), or "common," hence its name. The analogous bipolar junction transistor circuit is the common-base amplifier.