This half wave voltage signal is fed to the base of a switching transistor T, whose collector lead is coupled across {HEAD ~ a resistor RC} to {TAIL ~ the positive power supply voltage} of the apparatus 
to
This half wave voltage signal is fed to the base of a switching transistor T , whose collector lead is coupled across { HEAD ~ a resistor RC } to { TAIL ~ the positive power supply voltage } of the apparatus
OTH OTH OTH OTH 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 REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH