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