In an electrosurgical generator for generating radio frequency power, the generator comprises a radio frequency output stage having three or more output connections, one or more sources of output power coupled to the output stage, and a controller operable to cause the generator to supply a first cutting RF waveform to the output connections or a second coagulating RF waveform to the output connections. In a combined mode, the controller causes the generator to deliver both first and second RF waveforms, the controller including means for feeding the waveforms to the output connections such that the first RF waveform is delivered between a first pair of the output connections, and the second RF waveform is delivered between a second pair of the output connections. The combined mode is adjustable between various settings, each setting having a different proportion of the first and second RF waveforms. In response to a operator-actuated input signal, the controller causes the generator to supply an output waveform starting at a predetermined start setting, ending at a predetermined end setting, and changing between the start and end settings according to a predetermined progression.