The controller 52 uses this approximate average to control the magnitude of {HEAD ~ power} to {TAIL ~ both electrodes} 
The controller 52 uses this approximate average to control the magnitude of { HEAD ~ power } to { TAIL ~ both electrodes }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH TAIL TAIL TAIL TAIL TAIL TAIL