An electrosurgical system includes a generator for generating radio
frequency power, and an electrosurgical instrument including at least
three electrodes and. The generator includes a radio frequency output
stage having at least a pair of RF output lines, and a power supply
coupled to the output stage for supplying power to the output stage. A
controller is operable to limit the radio frequency output voltage
developed across the output lines to at least a first predetermined
threshold value to produce a cutting RF waveform, and a second threshold
value to produce a coagulating RF waveform. In a combined mode, the
controller delivers both cutting and coagulating waveforms by alternating
discontinuously between the first and second threshold values to form a
blended signal. The system also includes means for feeding the waveform
to the three or more electrodes such that the cutting RF waveform is
delivered between a first pair of the electrodes, and the coagulating
waveform is delivered between a second pair of the electrodes.