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, either simultaneously or by alternating constantly 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.