means for regulating comprises {HEAD ~ a transistor circuit} for controlling {TAIL ~ the discharge current} from the source of laser light 
for controlling
means for regulating comprises { HEAD ~ a transistor circuit } for controlling { TAIL ~ the discharge current } from the source of laser light
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH