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