Abstract: A control unit for use with a hand-held probe and an electrosurgical generator is disclosed to include a power input transformer which isolates the primary power supply from two electrically isolated circuits within the control unit. A first one of the electrical circuits receives a channel select signal from a hand-held probe connected thereto and, in response thereto, actuates either a first channel circuit or a second channel circuit within the second circuit. Each of the first and second channel circuits includes an alternating current actuated relay for electromagnetically moving a switch element therein in response to the channel select circuit so that either a first or a second control signal is provided to the electrosurgical generator.