TIL I was using my multimeter wrong for like 5 years straight

So I do HVAC work independently now and I always thought I knew how to check a capacitor with my meter. Like you just touch the leads and see if it reads something, right? Wrong. One day last spring I was trying to diagnose a blower motor that kept tripping and this old timer at the supply house was like "you gotta put it in capacitance mode first, then discharge it or you're just guessing." He showed me on his meter and I felt like a complete idiot. I had been misreading bad capacitors as good and good ones as bad for years. Probably cost me a few return trips to customers. Anyone else have a moment where a simple tool trick made you realize you'd been doing it backwards the whole time?

2 comments

2 Comments

sanchez.pat1mo ago

Gonna push back a little, I still think most multimeters are pretty straightforward in auto mode unless you're dealing with something weird. But fair play to that old timer for showing you the capacitance setting, that part can be tricky.

juliashah1mo agoMost Upvoted

Oh come on, you really think auto mode is that simple? I've seen people grab a multimeter and get a totally useless reading because they didn't realize the leads were in the wrong jacks for what they were trying to measure. Auto mode just picks a range, it doesn't tell you if you're trying to read AC voltage when you actually need DC, or if your probes are plugged into the amp port instead of the volt port. And don't get me started on continuity testing - half the newbies I've handed a meter to couldn't figure out why it was beeping at them until I showed them the diode check symbol. That old timer probably saved the guy a lot of frustration by walking him through the capacitance thing, because auto mode sure as heck isn't going to sort that out for you.