HF surgical appts. with load dependent performance control - has feed source controlled by combination of negative and positive feedback of electrode voltage and current

摘要

The appts. contains surgical electrodes, a generator supplying HF energy to the electrodes, and a controllable source (2) feeding the generator. The source is controlled in dependence of the impedance between the electrodes. The source control depends on a combination of a negative feedback of a voltage at the electrodes, and a positive feedback of a current flowing through the electrodes. Pref. the rate of the positive current feedback is adjustable for taking into account the size of the tissue portion engaged by the surgical step. The negative feedback adjustment may be proportional to voltage level at the electrodes. USE/ADVANTAGE - For coagulation surgery, with low-cost reliable design.