Author Topic: Bad condenser? How to test?  (Read 4673 times)

Offline benhutcherson

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Re: Bad condenser? How to test?
« Reply #15 on: January 29, 2009, 09:35:45 PM »
As you may or may not know, a capacitor is a two conductive surfaces separated by some sort of dielectric.

The radio capacitors that fail are usually either electrolytic capacitors or paper capacitors. Paper capacitors, of course, use paper as the dieletric, which can break down over time. Eventually, the paper can become so fragile that current will arc through the paper, closing the circuit and short circuiting the capacitor.

Electrolytic capacitors have a sheet of aluminum in contact with a conductive goo(electrolyte). The dielectric is a thin layer of aluminum oxide on top of the aluminum. The aluminum oxide can break down over time. which renders the capacitor useless. Of course, it's also easy to regenerate with low current. The electrolyte can also dry out, however, which permanently kills the capacitor.

There are other dielectrics used, such as ceramic, mylar, tantalum, or even air or a vacuum. These do not generally have problems.

I'm not sure what type of capacitors telephones use, however we can safely assume that they're of a type whose dielectric doesn't break down. Given the large physical size and relatively low values, it wouldn't surprise me if they use air as the dielectric.

Offline Dan/Panther

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Re: Bad condenser? How to test?
« Reply #16 on: January 29, 2009, 10:01:44 PM »
Is that called a "Multi Meter"??
Yep, exactly.

I'm sorry are we talking about the same meter. The one I posted is just for capacitance, not voltage, or resistance.
Mine is not a multimeter.
I think we must be referring to two different meters.

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Offline bingster

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Re: Bad condenser? How to test?
« Reply #17 on: January 29, 2009, 10:17:00 PM »
Sorry, I didn't check back to your original post, Dan.  Multimeters were mentioned at the beginning of the thread and I had that in my mind.  Mine does test for capacitance, though.

Offline Dennis Markham

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Re: Bad condenser? How to test?
« Reply #18 on: January 30, 2009, 12:02:25 AM »
Thank you for the information guys.  I'm going to have to learn a little bit of this electrical stuff.