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Polarized vs Mon Polarized Capacitors

I have a small project to make where I need to provide DC isolation for a low impedence audio circuit. I need a non-polarized capacitor of about

100 uf. Failing this, what would be the impact of two 220 uf polarized electrolytic capacitors in series? The latter would be more easily obtained. This is a one time project so buying parts in bulk is not an option. 
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Joe Leikhim K4SAT
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"Treason doth never prosper: what's the reason?
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**THE-RFI-EMI-GUY**
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A clamping diode in parallel with each capacitor wouldn't hurt, just to make sure reverse charging can't happen!

Reply to
ian field

In order to get 100uF with two caps in series, they will each need to be 200 ( 220 ) uF. I have seen this done many times to produce a bipolar electrolytic. Usually, it's the two " - " terminals that are joined, leaving the two " + " terminals for connection. I don't know whether there's some valid reason for this. I seem to remember reading in the dim distant past, that it's something to do with which is the outer foil in the cap, but I don't really see why this should make any difference, and I'm sure it won't in an audio coupling application. 'Genuine' bipolars are readily available in this sort of value.

Arfa

Reply to
Arfa Daily

In my experience non-polar electrolytics have tended to be unreliable, expensive & oversized!

Reply to
ian field

i've seen many used like that with an encapsulated package to make it look like a single. btw. i could be wrong here but if your looking for

100 uf then i think you should keep with using 2 100 uf in series because one is going to short while the other charges and they need to be back to back of course. 
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Reply to
Jamie

Hi Ian Yeah, interesting you should say that. They do tend to be bigger, although I'm not sure that I've really found them any less reliable. Even given that they are bigger, I guess that one of them has still got to take up less board space than two regulars back to back, though.

Arfa

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Arfa Daily
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Thanks all for the >

--
Joe Leikhim K4SAT
"The RFI-EMI-GUY"©

"Treason doth never prosper: what's the reason?
For if it prosper, none dare call it treason."

"Follow The Money"  ;-P



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Thanks all for the input. Joe

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          **THE-RFI-EMI-GUY** wrote:

          
          
            I have a small project to make where I need to provide
DC isolation 
for a low impedence audio circuit. I need a non-polarized capacitor of 
about 100 uf. Failing this, what would be the impact of two 220 uf 
polarized electrolytic capacitors in series? The latter would be more 
easily obtained. This is a one time project so buying parts in bulk is 
not an option.

            
          
          i've seen many used like that with an encapsulated
package to make it look like a single.
 btw.
  i could be wrong here but if your looking for
100 uf then i think you should keep with using
2 100 uf in series because one is going to short
while the other charges and they need to be back to
back of course.
Reply to
**THE-RFI-EMI-GUY**

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