a relay having a coil connected to the collection terminal of the transistor and {HEAD ~ a switch} connected between the power output terminal and {TAIL ~ the power output socket} 
a relay having a coil connected to the collection terminal of the transistor and { HEAD ~ a switch } connected between the power output terminal and { TAIL ~ the power output socket }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL