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