High-frequency current generator for tissue cutting or coagulation

摘要

The generator is based on a transformer (1) whose single secondary winding has terminals connected by a low-pass filter (F) to a two-wire cable (R). The filter comprises three inductors (6-8) and the capacitance of a toroidal magnetic circuit (9) wound with a low-capacitance two-wire cable connected to the output by series capacitors (11,12) and a shunt resistance (13). The dimensioning of the filter allows for the stray capacitance (14) of the output cable so that the electrodes of the instrument (5) receive power within a relatively narrow range of values while the interelectrode load resistance may vary by hundreds of ohms.