a thyristor free wheeling diode connected in {HEAD ~ antiparallel relationship} with {TAIL ~ the respective thyristor} 
with
a thyristor free wheeling diode connected in { HEAD ~ antiparallel relationship } with { TAIL ~ the respective thyristor }
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL