Tried a cheap capacitor tester from harbor freight and got some weird readings

I picked up one of those little component testers for about 15 bucks last month just to check some microwave caps. Threw a 10uF 250V cap on it that I knew was good from a working board and it showed 8.2uF with a high ESR. Tested the same cap on my buddy's fluke meter and it came back at 10.1uF with normal ESR. Guess you really get what you pay for with test gear. Anyone else run into false readings from those cheap all-in-one testers?

2 comments

2 Comments

casey_barnes5d ago

...and that's actually a really common mistake people make with those cheap testers. The ESR reading on those little things isn't reliable at all, especially for electrolytic capacitors. They usually run at a fixed frequency that doesn't match what the cap would see in a real circuit, so the ESR number is basically made up. You're right to double check with a known good multimeter. Have you tried testing a few different values to see how far off the readings get?

spencer_sanchez675d ago

Whoa, I gotta push back a little on the Fluke being a perfect reference though. Even good multimeters can have their own quirks with capacitance readings, especially on board.