MJLorton Solar Power and Electronic Measurement Equipment Forum

General Category => General Discussion => Topic started by: cossy350 on November 14, 2014, 05:47:28 PM

Title: help ers table
Post by: cossy350 on November 14, 2014, 05:47:28 PM

hi all i am looking for a good esr table i can find some on google but not the cap i have it is a 150uf at 400v i tested is and it was 134uf and the esr was  0.08 ohm is that good or bad

Title: Re: help ers table
Post by: TechJunkie on November 15, 2014, 05:37:02 PM

Assuming that you are testing an electrolytic, 134uF for a 150uF is fairly common for a lot of electrolytic capacitors. The ESR is really low for that voltage and value. What was your test frequency? Is this an ultra low ESR capacitor? I am not saying the capacitor is bad, a .08 Ohm ESR is very good. Typically for a 400V capacitor, an ESR of around .5 or lower is good. Anything above that starts to get a bit dodgy. I would be curious as to the capacitor brand and type.

Title: Re: help ers table
Post by: Mr Eastwood on November 15, 2014, 05:42:22 PM

Not sure about the ESR value, I use one of these..

(http://www.dyinstrument.com/products/images/294.jpg)

http://www.dyinstrument.com/duoyi/?q=transistor_tester/DY294 (http://www.dyinstrument.com/duoyi/?q=transistor_tester/DY294)


If you discharge it first then take it up to it's working voltage eg. 400V - if it's slow compared to a new one,  or leaky - then i just throw them away!

Title: Re: help ers table
Post by: retiredcaps on November 19, 2014, 07:32:05 PM

There isn't one really one good ESR table.  Manufacturers make different types of capacitors.  Some are "entry level" ESR and some are "ultra low" ESR.  Some caps are general purpose and won't have an ESR value listed in the datasheet.

It is best to view each manufacturer's datasheet and verify if the cap in question is within its stated parameters.