Abstract: Electrosurgery apparatus has a processor that generates a data stream output representing the characteristics of the electrosurgery pulses to be generated. The data stream output comprises digitally-represented values indicative respectively of the width of each pulse, the duration of a first period during which pulses are to be generated, the duration of a second period during which pulses are not to be generated, the duration of a third period during which pulses are to be generated and the duration of a fourth period during which pulses are not to be generated. The data stream also includes digital instructions as to whether or not the electrosurgery output is to be cut only and whether it is to include spray coagulation. Three switch control units receive the data stream and provide outputs to three switching circuits, which provide two monopolar and one bipolar output. Each switching circuit includes a transformer connected to receive the outputs from the switch control units.

Abstract: Electrosurgery equipment has an alarm circuit for detecting when a return plate electrode is incorrectly attached. Capacitive dividers are connected between ground and each of the power supply line to the active electrode and the power supply return line from the plate electrode. The outputs of the capacitive dividers are supplied to the two inputs of a differential amplifier which provides an output to one input of a comparator. Another input of the capacitor is connected to a reference source. When the output of the differential amplifier rises above the reference source, the comparator produces an alarm signal which inhibits the power supply and gives an audible alarm.