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