What is this electrical component "CR"? Hey folks, Can anyone give me a hint to what the CR symbol in this wiring diagram might mean? I'm thinking it is some kind of switch... The equipment is a solar cell tester. Basically it traces I-V curves. In the attached picture the pins (circles) contact the solar cell (anode and cathode on the back) It looks like VB+ is always at the IV-Voltage+ potential. PPV-Test-1 (carried on a BNC cable to an analog card on the control PC) must compare VA+ to VB+ (for some nefarious purpose) but unless CR20 causes some potential drop I don't know why VA wouldn't simply equal VB; unless there was some defect across the solar cell. The original owner used this equipment for QC so that wouldn't surprise me. And yes, off to the right hand side is the IV-Voltage- and IV-Current- side. Any insight or any helpful references would be a godsend. I'll eventually figure the whole thing out but "cheating" a bit never hurts!