The rate of change of the flux in the primary winding induces a voltage in {TAIL ~ a sensing winding}, which voltage is integrated and used to control the on time of {HEAD ~ the switching device} so as to control the flux in the main coil 
The rate of change of the flux in the primary winding induces a voltage in { TAIL ~ a sensing winding } , which voltage is integrated and used to control the on time of { HEAD ~ the switching device } so as to control the flux in the main coil
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH