On Tue, 17 Jun 2014 16:50:40 -0500, "Dave" <db5151@hotmail.com> wrote as underneath :>I have an LCR meter which shows the ESR for electrolytic caps, but I have no >idea how to interpret this number. How do you know if a cap is shorted or >boardering on that status? I mean, if it gives me a reading of zero Ohms, >that's obvious, but what if a small (4.7uF), medium voltage (35V) cap comes >up with a reading of, say, 3 Ohms? Is that too low, like I expect, or >should it be considered acceptable? I just don't know what a good cap would >likely register, and have been surprised in the past when a brand new cap >registered a lower ESR than the one I thought was bad. Where can I find >info on the subject? Any ideas are welcome. > >Thanks... > >Dave >This might be helpful to you - its a link to the Peak ESR meter instruction manual which has a chart on page 9 uF/voltage/ESR approx expected in average conditions. http://www.peakelec.co.uk/resources/esr60_userguide_en.pdf C+
? on old electrolytic caps
Started by ●June 17, 2014
Reply by ●June 20, 20142014-06-20
Reply by ●June 20, 20142014-06-20
On Fri, 20 Jun 2014 06:57:50 +0100, Charlie+ <charlie@xxx.net> wrote:>On Tue, 17 Jun 2014 16:50:40 -0500, "Dave" <db5151@hotmail.com> wrote as >underneath : > >>I have an LCR meter which shows the ESR for electrolytic caps, but I have no >>idea how to interpret this number. How do you know if a cap is shorted or >>boardering on that status? I mean, if it gives me a reading of zero Ohms, >>that's obvious, but what if a small (4.7uF), medium voltage (35V) cap comes >>up with a reading of, say, 3 Ohms? Is that too low, like I expect, or >>should it be considered acceptable? I just don't know what a good cap would >>likely register, and have been surprised in the past when a brand new cap >>registered a lower ESR than the one I thought was bad. Where can I find >>info on the subject? Any ideas are welcome. >> >>Thanks... >> >>Dave >> >This might be helpful to you - its a link to the Peak ESR meter >instruction manual which has a chart on page 9 uF/voltage/ESR approx >expected in average conditions. >http://www.peakelec.co.uk/resources/esr60_userguide_en.pdf >C+--- That's a keeper! Thanks. :-)
Reply by ●March 1, 20212021-03-01
On 6/19/2014 2:18 PM, John Fields wrote:> On Thu, 19 Jun 2014 17:19:00 +0000 (UTC), Cydrome Leader > <presence@MUNGEpanix.com> wrote: > >> Maynard A. Philbrook Jr. <jamie_ka1lpa@charter.net> wrote: >>> In article <b243q9t7gq15ragisjeqisjkn30iib91do@4ax.com>, >>> jfields@austininstruments.com says... >>>> The resistance of a capacitor is an entirely different thing, and >>>> amounts to the leakage current measured through the dielectric with >>>> a voltage across it. >>>> >>>> In terms of goodness, the lower the ESR and the higher the >>>> resistance the better. >>>> >>>> John Fields >>>> >>> Could you please clarify that a bit? I am only an >>> inbred from Maine and I did quite get that one. >> If you take an electronic device, even something simple like a battery >> there are still losses inside the device from the wiring, connections and >> other electrochemical stuff going on inside the device. >> >> Those internal losses are what's called ESR. For instance, if you short >> out a AAA battery you will get less current than if you short out a D >> cell, even though both can in theory output 1.5V. The D cell has beefier >> internal construction and offers a lower internal resistance, so more >> current can be drawn from it. >> >> The tricky part is a battery, (or capacitor or anything really) is not a >> plain resistor, so you can't measure this "equivalent" value with an ohm >> meter, but if you could, the result would be the ESR. >> >> In capacitors, you generally want the lowest possible ESR. A cap with a >> high ESR is old, failing, cheap or just junk, and it can potentially heat >> up during use, just like a resistor. Heat makes electrolytic capacitors >> dry up, which increased the ESR, which make them heat up more, until they >> explore or just stop being capacitors. > --- > Right. > > They turn into explorers. ;) > > John Fields The third picture (schematic) has a slightly simplified schematic of a capacitor with it's ESR, leakage and inductance.> https://www.designworldonline.com/basics-of-tantalum-electrolytic-capacitors/ I think this may help you understand, and why, each must be measured differently. Mikek -- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus
Reply by ●March 1, 20212021-03-01
On 3/1/2021 7:54 AM, amdx wrote:> On 6/19/2014 2:18 PM, John Fields wrote: >> On Thu, 19 Jun 2014 17:19:00 +0000 (UTC), Cydrome Leader >> <presence@MUNGEpanix.com> wrote: >> >>> Maynard A. Philbrook Jr. <jamie_ka1lpa@charter.net> wrote: >>>> In article <b243q9t7gq15ragisjeqisjkn30iib91do@4ax.com>, >>>> jfields@austininstruments.com says... >>>>> The resistance of a capacitor is an entirely different thing, and >>>>> amounts to the leakage current measured through the dielectric with >>>>> a voltage across it. >>>>> >>>>> In terms of goodness, the lower the ESR and the higher the >>>>> resistance the better. >>>>> >>>>> John Fields >>>>> >>>> Could you please clarify that a bit? I am only an >>>> inbred from Maine and I did quite get that one. >>> If you take an electronic device, even something simple like a battery >>> there are still losses inside the device from the wiring, >>> connections and >>> other electrochemical stuff going on inside the device. >>> >>> Those internal losses are what's called ESR. For instance, if you short >>> out a AAA battery you will get less current than if you short out a D >>> cell, even though both can in theory output 1.5V. The D cell has >>> beefier >>> internal construction and offers a lower internal resistance, so more >>> current can be drawn from it. >>> >>> The tricky part is a battery, (or capacitor or anything really) is >>> not a >>> plain resistor, so you can't measure this "equivalent" value with an >>> ohm >>> meter, but if you could, the result would be the ESR. >>> >>> In capacitors, you generally want the lowest possible ESR. A cap with a >>> high ESR is old, failing, cheap or just junk, and it can potentially >>> heat >>> up during use, just like a resistor. Heat makes electrolytic capacitors >>> dry up, which increased the ESR, which make them heat up more, until >>> they >>> explore or just stop being capacitors. >> --- >> Right. >> >> They turn into explorers. ;) >> >> John Fields > > The third picture (schematic) has a slightly simplified schematic of > a capacitor with it's ESR, leakage and inductance. > >> https://www.designworldonline.com/basics-of-tantalum-electrolytic-capacitors/ >> > I think this may help you understand, and why, each must be measured > differently. > > Mikek > >I must have reversed my date orientation when I answered this. Then I noted John Fields name and thought, I think he died! Anyway, I made a fine contribution to a 6 year old thread. Mikek -- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus
