Capacitor ESR

[davmax]

Capacitor ESR is often raised as an issue. The following link gives a good explanation of ESR and related capacitor characteristics.

http://xtronics.com/reference/esr.htm

[redassa]

Re: Capacitor ESR

Hello,
I Wanted To Ask About The Relation Between ESR For Caps & The Power Sustained & If Leakage Current Is Related To That ESR?
Thanx

[bazatheman]

Re: Capacitor ESR

The first thing I thought about after reading a few posts on here was ... I must invest in a ESR meter and understanding the characteristics of capacitors is a good learning investment .
Know thy enemy... with all the bad caps out there causing untold damage to our electronics I will be working on my knowledge base... Cheers.. Barry

[blouis79]

Re: Capacitor ESR

I got the impression ESR is important and that caps can test OK on other paremeters but if ESR is wrong, they won't work.

I read that Bob Parker seems to have credit for inventing ESR meters. Has lots of info on ESR meter kits.
http://members.ozemail.com.au/~bobpar/esrmeter.htm

Looking around at various ESR meter kits, I found Peak Electronics UK - fully built ESR meters. I got several of their meters and have found them really useful, since they measure a load of thing my Fluke multimeter won't do. I bought direct from Peak for a lot less money than I could find locally.
http://www.peakelec.co.uk/acatalog/jz_instruments.html

[Hop Tzop]

Re: Capacitor ESR

Hi everyone,

I am new and I can't start a new thread. I'm looking in changing some electrolytic capacitors on a Gigabyte P35-S3G, near ram. I've already replaced 2 of them, but two others gone bad and I'm thinking on replacing all of them with polymer capacitors. Then searching on the internet I came on ESR. I've read that they should have different capacity if you replace electrolytic ones with polymer.

My actual capacitors are 6.3V, 1000uF and I've found polymer capacitors with the same ratings, 6.3V, 1000uF and ESR 7 mOhms. Would that be good for my motherboard?

Description of the polymer capacitor.

Manufacturer: Nichicon
Product Category: Aluminum Organic Polymer Capacitors
RoHS: RoHS Compliant Details
Product Type: Can
Capacitance: 1000 uF
Voltage Rating DC: 6.3 V
Tolerance: 20 %
ESR: 7 mOhms
Termination Style: Radial
Minimum Operating Temperature: - 55 C
Maximum Operating Temperature: + 105 C
Case Length: 12.5 mm
Case Diameter: 10 mm
Lead Spacing: 5 mm
Operating Temperature Range: - 55 C to + 105 C
Packaging: Bulk
Product: Organic Polymer Aluminum - Radial Capacitors
Series: R7
Tradename: FPCAP

[Sai Peregrinus]

Re: Capacitor ESR

The following site is a good resource of ways to measure ESR, from manual methods with oscilloscope & function gen through DIY kits to commercial devices. Don't try to do it in-circuit, at least lift one leg of the capacitor under test.

[Sai Peregrinus]

Re: Capacitor ESR

The following site is a good resource of ways to measure ESR, from manual methods with oscilloscope & function gen through DIY kits to commercial devices. Don't try to do it in-circuit, at least lift one leg of the capacitor under test.

http://kripton2035.free.fr/esr-repository.html


It would have helped to include the URL, wouldn't it?

[Behemot]

Re: Capacitor ESR

most of the instruments there are obsolete (like that ESR Micro v4.0 leading to who knows what website, I resell v5.0S/+ for like 3 years now) and there is no reason to unsolder every cap, that would be insane nightmare to do pretty much anything

[japlytic]

On a related topic, ESL (Equivalent Series Inductance) which increases with case size which can reduce the usefulness of the capacitor to high slew-rate trensient loading - this parameter is typically not specified by manufacturers of electrolytic capacitors and I've read that in most cases, multiple electrolytic capacitors of small case size perform better than a single large case capacitor.