Yet another electronics question: Testing tantalum & ceramic capacitors without a capacitance meter. Any way to do it?

[Jeff7]

These questions will likely keep coming here until I find a good electronics forum and/or very excellent textbook. 😉

This damaged board here has a bunch of ceramic and tantalum capacitors on it, rated anywhere from 33pF to 1uF, at up to $1 each.
The best I've got is a DMM. Besides voltage and amperage, it can only do resistance and diode testing.

Is there any way of testing capacitors of such low values without a dedicated capacitance meter?


Additional: What's the average lifespan of ceramic and tantalum capacitors? These particular parts were likely made in the early 80s.

 

[Rubycon]

Most non electrolytics last very long unless abused. Tantalums often fail spectacularly with pyrotechnic glory!

You definitely should retain a capacitance meter if you want to even get close to values. A DMM/VTVOHM is good for testing function of capacity but that's it.

 

[Jeff7]

My own DMM is only good for up to 400nF.
Really large caps, such as the 10,000uF servomotor starter caps, I can test those with a discharge test through a resistor, while measuring the voltage level. That's fairly straightforward.

And that's part of the problem - I don't know if these caps were abused. They were on a board which was abused, I just don't know if they were caught in the other pyrotechnics that were occurring. 🙂

Even more fun, the DMM I have at work won't even work for very basic MOSFET testing, as its diode test voltage is only 1.5V. I apparently need at least 3V to get a MOSFET to open...or close...or whatever it should do to tell me if it's doing anything that it should be doing.
From what I've seen of specsheets, a good way to test a MOSFET would be with some kind of signal generator, which of course I don't have. 🙁

 

[Rubycon]

Signal generators are easy to make. You can use an audio amplifier and a pc with a sound card for the source. If you need infrasonic signals you will have to modify the amp to be capable of working with DC.

A variable power supply that's well regulated/filtered should also be on your bench.

 

[Jeff7]

Originally posted by: Rubycon
Signal generators are easy to make. You can use an audio amplifier and a pc with a sound card for the source. If you need infrasonic signals you will have to modify the amp to be capable of working with DC.

Ah, right, I seem to recall hearing something like that somewhere. 😛
Coupled with Goldwave's function generator feature, I could probably create nearly any waveform.
If I can get ahold of a decent audio amplifier....

A variable power supply that's well regulated/filtered should also be on your bench.

Yes, it should be.

Have I mentioned lately that I have rather limited resources at work? :Q