US Patent 8926607 Electrosurgical instrument employing multiple positive temperature coefficient electrodes

An electrosurgical surgical instrument can comprise a handle and an end effector, wherein the end effector can comprise first and second jaws which can be opened and closed in order to capture tissue therebetween. In various embodiments, the first and second jaws can comprise one or more electrodes configured to apply a voltage across the tissue, wherein one or both of the first and second jaws can include a plurality of electrodes each comprised of a positive temperature coefficient material having a different switching temperature. The electrical resistances of the electrodes can increase significantly once the temperature of the electrodes exceed their switching temperatures and, owing to the increased electrical resistance, the flow of current through the electrodes can be reduced and/or prevented. In various circumstances, the different switching temperatures of the electrodes can allow some of the electrodes to switch off before the other electrodes.