{HEAD ~ Two operational amplifiers} 68 and 70 form {TAIL ~ part} of circuit 50 with inverting terminal 72 of op amp 68 common with anode 54 of photodiode 52 
form
{ HEAD ~ Two operational amplifiers } 68 and 70 form { TAIL ~ part } of circuit 50 with inverting terminal 72 of op amp 68 common with anode 54 of photodiode 52
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH