The duty cycle of the train of {TAIL ~ pulses} produced by the controller 14 and which are fed to the base of electrodes of transistors Q1 and Q2, is determined by the sense voltage produced on {HEAD ~ line} 17 
The duty cycle of the train of { TAIL ~ pulses } produced by the controller 14 and which are fed to the base of electrodes of transistors Q1 and Q2 , is determined by the sense voltage produced on { HEAD ~ line } 17
OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH