This seems like it should be simple, but I'm having trouble working through the logic.
I use two different testers to verify continuity on circuit boards. Both work by sending a constant current through the trace to be measured, measure the resulting voltage drop, and calculate the trace resistance. (Also, both testers have some cabling involved so the resistance is actually across the trace plus the cabling).
Anyway, one tester can use up to 200mA for the stimulus current, while the other is limited to about 5mA. Some boards will require a resistance of less than 5 Ohms on these continuity tests. I'll have much better luck measuring less than 5 Ohms using the tester than can push 200mA for the stimulus current.
Is there some simple explanation for why this may be?
Thanks!
I use two different testers to verify continuity on circuit boards. Both work by sending a constant current through the trace to be measured, measure the resulting voltage drop, and calculate the trace resistance. (Also, both testers have some cabling involved so the resistance is actually across the trace plus the cabling).
Anyway, one tester can use up to 200mA for the stimulus current, while the other is limited to about 5mA. Some boards will require a resistance of less than 5 Ohms on these continuity tests. I'll have much better luck measuring less than 5 Ohms using the tester than can push 200mA for the stimulus current.
Is there some simple explanation for why this may be?
Thanks!