Bias for transistor 168 is provided by {HEAD ~ current} via return resistor 174 coupled between the base thereof and {TAIL ~ the voltage source A} 
Bias for transistor 168 is provided by { HEAD ~ current } via return resistor 174 coupled between the base thereof and { TAIL ~ the voltage source A }
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL