Fun fact, in British English the term for a vacuum tube triode is "valve" precisely because it operates like a valve. FETs (particularly JFETs) follow the same analogy (which is why FET and triode amplifier circuits look basically the same) using the field effect instead of thermionic emission.
Fun fact, in British English the term for a vacuum tube triode is "valve" precisely because it operates like a valve. FETs (particularly JFETs) follow the same analogy (which is why FET and triode amplifier circuits look basically the same) using the field effect instead of thermionic emission.