A method of operating a electrosurgical instrument connected to an electrosurgical generator and comprising a circuit, a measurement unit and at least two electrodes, where the circuit controls a switching of the electrosurgical instrument between a measurement mode, where the measurement unit measures the impedance between the electrodes, and an operating mode, where the electrosurgical generator applies a voltage over the electrodes. The circuit comprises a timer that periodically controls the switching of the electrosurgical instrument between the measurement mode and the operating mode. An inexpensive electrosurgical instrument for use with most conventional electrosurgical generators as well as with electrosurgical generators specifically designed for use with said instrument is proposed.
