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Re: Topband: DX-100 adventure - progress

To: "'Tom W8JI'" <w8ji@w8ji.com>, "'Bill Cromwell'" <wrcromwell@gmail.com>, "'top Band'" <topband@contesting.com>
Subject: Re: Topband: DX-100 adventure - progress
From: "Charlie Cunningham" <charlie-cunningham@nc.rr.com>
Date: Sat, 21 Dec 2013 13:27:24 -0500
List-post: <topband@contesting.com">mailto:topband@contesting.com>
I REALLY don't care for connecting electrolytics in series. However, Bill
does say that the DX-100  already is configured with individual bleeders
across each capacitor in those series pairs - so he may be OK.



-----Original Message-----
From: Topband [mailto:topband-bounces@contesting.com] On Behalf Of Tom W8JI
Sent: Saturday, December 21, 2013 1:02 PM
To: Charlie Cunningham; 'Bill Cromwell'; 'top Band'
Subject: Re: Topband: DX-100 adventure - progress

> BTW, Biii - tip/suggestion  - for those series-connected electrolytics you
> probably should put a pair of equal value resistors - one across each 
> series
> capacitor, as the leakage currents will not be equal in each capacitor in
> each series string and the DC voltage won't divide equally across each
> capacitor unless you put individual "bleeder" or "swamping" resistors 
> across
> each cap in the series pair to equalize the DC across each capacitor in 
> the
> series!

It is worse than that.

With a single bleeder for two series capacitors, the capacitor with the 
least capacitance will always be reversed charged upon every power down. So 
even you have equal voltages by equal leakages, you have to add a parallel 
diode or the discharge will reverse charge the cap with the lowest 
capacitance value. 

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