{HEAD ~ The controller} generates {TAIL ~ an error signal} that PWMs the switch thereby controlling the heating element 
generates
{ HEAD ~ The controller } generates { TAIL ~ an error signal } that PWMs the switch thereby controlling the heating element
HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH