[sdiy] Trouble shooting cap's ESR values using 'acurate' table..

[rburnett at richieburnett.co.uk]

Capacitor ESR depends on a lot of things:  e.g. Capacitor construction, 
C/V ratio, temperature, capacitor aging, manufacturing tolerances, and 
the frequency at which the ESR test is being performed.

You can't say that a 100uF 63V electrolytic will typically have 1 ohms 
of ESR, because a brand-new low-ESR part might have a figure that's a 
tenth of this at the start of it's life when tested at a few hundred kHz 
and at a high operating temperature.

The best you can do for fault-finding is get a datasheet for the exact 
part that you're testing and repeat the ESR measurement under the same 
conditions used in the datasheet.  Obviously if your capacitor is 
towards the end of a hard life in a switched-mode power supply, it will 
likely measure with a higher ESR than a band-new one characterised in 
the datasheet.

-Richie,

On 2016-10-14 15:39, Jean-Pierre Desrochers wrote:
> Hi list,
> 
> I recently bought this multipurpose LCD meter for caps ESR checks:
> http://www.ebay.com/itm/-/121518679234?roken=cUgayN&soutkn=3AH3Nl
> 
> It's electrolytic caps ESR function seems to be quite precise
> even at that low price..
> Now I'm facing a problem. I need an acurate Cap ESR value table
> that has 'standard' values to check for when trouble shooting caps.
> The problem is that many of these table are on the net showing
> very different ESR values.
> Like this one:
> http://jestineyong.com/wp-content/uploads/2012/05/ESRTable11.jpg
> For example in some table 4700uf at 25vdc caps have 'standard' ESR values
> going from 0.12 down to 0.05 !!!
> I don't know which one to pick up for my tests..
> Any experiences with these tables you could share ?
> Thanks !
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