I have purchased a cheap digital panel meter (DPM). After I got the meter I found out what many people have found out. I can't power the meter from the same circuit that I'm trying to measure... At least not without isolation. I've been reading for a couple days now on this topic. I think I understand the *why* I need to isolate, because I can't measure something without having a independent baseline... However, whatever the reason I know I need one. So I've found online a few ideas but they are all a bit complicated for a newbie. Question, can anyone recommend some simple (newbie) reading on how to understand creating this separate (floating?) voltage and ground from the power supply in question? I've seen discussion around opto-couplers and 555 timers being used to make things work. But they are all completed circuits with no explanation of why they work or what the different parts are doing.
Any help would be great. I have some 555 chips, no opto-couplers, so perhaps something down that line would be most helpful. A common question I have from the diagrams I've seen is that they do all seem to use the same "ground" at some point. So I'd like to see discussion around what makes the "grounds" different.
Any help would be great. I have some 555 chips, no opto-couplers, so perhaps something down that line would be most helpful. A common question I have from the diagrams I've seen is that they do all seem to use the same "ground" at some point. So I'd like to see discussion around what makes the "grounds" different.