Electro-surgical HF instrument for contact coagulation - has monitoring circuit evaluating HF voltage at electrodes and delivering switch=off signal

摘要

The surgical instrument is connected to the h.f. leads output (33,34) of a h.f. generator (10) via a h.f. coupling transformer (11) to supply the electrodes (16,17,16',17'). A monitoring circuit (20) detects the voltage at the latter and evaluates it to deliver a switch-off signal to the h.f. generator. The monitoring circuit includes a differential circuit (21) with a d.c. voltage at its input that is proportional to the amplitude curve of the h.f. electrode voltage. Its output signal is delivered to a switch-off unit (23) actuating the h.f. generator. ADVANTAGE - Technically simple circuitry ensuring reliable automatic switching off of power after completion of contact coagulation. This ensures optimal result in each case.