The signal at the collector of transistor 168 is then applied to {HEAD ~ the base} of {TAIL ~ a current drive NPN transistor} 186 via a diode 178 
of
The signal at the collector of transistor 168 is then applied to { HEAD ~ the base } of { TAIL ~ a current drive NPN transistor } 186 via a diode 178
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH