DEVICE FOR COAGULATION AND/OR DISSECTION OF BIOLOGICAL TISSUE AND A METHOD OF OPERATING A DEVICE

A device and a method for coagulation and/or dissection of biological tissue is disclosed. The device comprises an apparatus and an instrument electrically connected thereto. The instrument includes an operation circuit with a manually operated switch. An evaluation circuit of the apparatus provides an evaluation signal for the instrument. The apparatus can create a supply voltage or a supply current for the instrument. In the initial condition the evaluation signal comprises only one polarity. The evaluation signal is provided to a control circuit of the instrument in which a characteristic of the evaluation signal is adjusted depending on the operating condition of the switch. The evaluation circuit detects this characteristic and initiates the output of the supply voltage and changes the polarity of the evaluation signal according to the requested cutting mode. In the cutting mode the evaluation signal comprises at least temporarily also a second polarity.