Disclosed is {HEAD ~ an electrical control circuit} for controlling {TAIL ~ current} through a furnace coil or other resistive load  
Disclosed is { HEAD ~ an electrical control circuit } for controlling { TAIL ~ current } through a furnace coil or other resistive load
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH