Cap reformation question

Chuck Guzis cclist at
Tue Dec 6 18:47:08 CST 2005

On 12/6/2005 at 7:03 PM Scott Stevens wrote:

>I would recommend using a high quality Constant Current/Constant
>Voltage bench supply.  These have a 'current' and a 'voltage' knob
>on them and two meters (someetimes one switchable meter).  The
>procedure I use is to set the voltage to the level that you want
>the capacitor to reach while disconnected.  Then turn the current
>limiting way down and connect the capacitor.  Monitor the current
>while turning it up slowly and leave it at some comfortable low
>level so the cap can form up.  This process limits the current
>while the cap forms up.  You can watch the voltage meter, which
>should climb up to what you had it set at, if the cap is any good.

Wouldn't this amount to the same thing as putting a hefty resistor in
series with a variac-controlled power supply with a voltmeter on the supply
side?  Start low--the resistor limits the current--crank the variac up bit
by bit until the desired voltage is reached.  A fuse isn't a bad idea
either, in case the dielectric just plain fails. 

It's worked for me.  And my power supply isn't anything more than a
transformer connected to the variac followed by a full-wave bridge
rectifier--no filtering needed.


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