A variety of surgical instruments include one or more elements that transmit RF energy to tissue. Some such instruments comprise a pair of jaws that open and close on tissue, with conductive tissue contact surfaces that are operable to weld tissue clamped between the jaws. Some surgical instruments also include a translating tissue cutting element. Some such instruments may be in the form of forceps having a scissor grip. Forceps type instruments may in some instances provide a feature that allows the jaws of the forceps to be locked on tissue, so that the operator can remove his or her hands from the instrument. In such an instrument it may also be desirable to provide a circuit that is activated only when the forceps are closed and sufficient pressure is applied to the tissue between the jaws of the device.
