A trigger coil generates {HEAD ~ a trigger signal} for {TAIL ~ application} to the trigger of the switches 
for
A trigger coil generates { HEAD ~ a trigger signal } for { TAIL ~ application } to the trigger of the switches
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH