The duty cycle of {HEAD ~ 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 line 17 
The duty cycle of { HEAD ~ 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 line 17
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL 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 OTH OTH