capacitor tester

[scole]

is there a simple device i could build to check the value of a capacitor, similar to the way you check a resistor with a dmm?

[Enzo]

I have seen circuits for that in the past as projects, but don;t recall where. But you can buy a modern inexpensive DMM that includes such function for not a lot of money.

With caps, especially older ones going leaky, it is not usually the value that suffers. A cap meter won;t tell you about leaky unless the cap is so leaky it upsets the meter reading.

[gmoon]

Got a LCR meter from Hong Kong off Ebay for ~$25 (shipping included.)

I wasn't crazy about buying cheap test gear from China, but it works pretty darn well (hey, I'm on a budget, too.) Really paid for itself when I sorted out all the various inductors tucked away here and there...

Also, it's kinda cool to see how close caps are to the labeled value (sometimes, not so close.)

[daz]

Whats odd is that i have a Fluke and a cheapo called a Extech i got from Fry's. The Extech reads caps just great, while the Fluke almost never reads anything. then again i use them mostly for very small caps like in the pf range. But still, you'd think the Fluke would work better let alnoe not as good or not at all ! If i recall the Extech was only something like $20-30. The fluke was $120 or thereabouts. So much for getting your money's worth i guess.

[doctorvoltz]

I also post on an antique radio restoration forum. I found a circuit on there for a simple capacitor leakage tester that applies between 200-300 volts to test a cap for leakage. I built it and it works like a charm. When an old tube amp cap goes bad, value doesn't change, it either shorts or gets leaky. This tester makes finding leaky and shorted caps a snap. Here is the link complete with schematics. All of the circuits are similar and will work. Antique Radio Forums :: View topic - Easy to build capacitor checker A must for checking parts .