Capacitor testing - how do you do it?
Robert A. Williams
Can anyone tell me the proper way to test an electrolytic capacitor? Leak
test? I've read a lot of different view points on this one, but there
doesn't seem to be any consistancy. I'm also looking to buy a good DMM.
Any pointers? Maybe one that tests capacitors thoroughly.
Thanks,
Rob Williams
alone ranger
Fluke makes a good multi-meter that also checks caps. Also get a ESR
meter they are better at checking caps in circuit.
Sam Goldwasser
In article <68hqs9$bg2$1...@akron5.neo.lrun.com> "Robert A. Williams" <rwil...@neo.lrun.com> writes:
> Can anyone tell me the proper way to test an electrolytic capacitor? Leak
> test? I've read a lot of different view points on this one, but there
> doesn't seem to be any consistancy. I'm also looking to buy a good DMM.
> Any pointers? Maybe one that tests capacitors thoroughly.
For repair work, an ESR tester is probably most useful since in most cases
it will work in-circuit. Swapping it the only sure test :-).
--- sam : Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Lasers: http://www.geocities.com/CapeCanaveral/Lab/3931/lasersam.htm
Usually latest (ASCII): http://www.pacwest.net/byron13/sammenu.htm
Petercoe
>Can anyone tell me the proper way to test an electrolytic capacitor? Leak
>test? I've read a lot of different view points on this one, but there
>doesn't seem to be any consistancy. I'm also looking to buy a good DMM.
Here's what works for me. If the capacitor is used for filtering I turn the
equipment on and measue the ac voltage across the cap. The reading will go
from high to zero if the capacitor is not leaky. The high to zero also tells
me approximate capacitance by seeing how long it takes to go to zero. If the
capacitor is used for coupling an oscilloscope will show if it is coupling. In
most cases, if I'm suspicious, I just try another capacitor.
Pete...@aol.com
35 year tv repair
Christopher Morin
How does one test a cap that has four leads? I've got two huge filter caps
next to a transformer and I don't know how to figure out if they're leaking
or not. They have three leads next to each other in an arc and one off by
itself.
.christopher.
Petercoe <pete...@aol.com> wrote in article
<19980103013...@ladder02.news.aol.com>...
Sam Goldwasser
In article <01bd19b4$de0948c0$1bec...@sirius.com.sirius.com> "Christopher Morin" <ch...@sirius.com> writes:
> How does one test a cap that has four leads? I've got two huge filter caps
> next to a transformer and I don't know how to figure out if they're leaking
> or not. They have three leads next to each other in an arc and one off by
> itself.
Usually, this means there are actually three capacitors sharing a common
(negative) usually. So, test it like 3 separate caps.
As far as the overload, you should try disconnecting each output in turn
to see which one is causing the problem since this could be an overload
downstream. Caps can short but this is less likely. Dried up caps can
result lin hum and other problems but not likely to overheat the
transformer.
Petercoe
>How does one test a cap that has four leads? I've got two huge filter caps
>next to a transformer and I don't know how to figure out if they're leaking
>or not. They have three leads next to each other in an arc and one off by
>itself.
You probably have three capacitors in one package with one common for all
three. The three leads next to each other are the three capacitor positive
leads. The one by itself is the common negative lead.