a solid state version of the triode
1st created in 1947
the metal–oxide–semiconductor field-effect transistor (MOSFET) is the most commonly used type (99.9% of all currently used) and was invented in 1959 and revolutionised the field of electronics.
is used as an on/off switch or amplifier
it is composed of semiconductor material, usually with at least three terminals - field effect transistors - FET - have four terminals named source, gate, drain, and body (substrate).
a voltage or current applied to one pair of the transistor's terminals controls the current through another pair of terminals.
the controlled (output) power can be higher than the controlling (input) power, a transistor can thus amplify a signal.
integrated circuits consist of many transistors