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 Post subject: High esr miec electrolytic aluminum capacitors
PostPosted: Aug Fri 09, 2019 4:21 pm 
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Joined: Sep Sun 02, 2012 5:58 am
Posts: 146
Location: San Manuel AZ
Hello everyone , I have a question about esr and aluminum ELECTROLYTICS capacitors. I just recently purchased miec
Caps. 8uf 600v and 4uf 600v. The esr reads very high 6ohm to 11 ohm esr. However, they all test good for leaking on my sprague to-4 analizer. With esr that high, I would think that they would have leakage. The esr readings are taken using 1khz, 10khz, 100khz, 120khz. On my DE-5000 and Mser-100. Also I can't find any data sheets on these.

Thankyou for your feedback

Mike


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 Post subject: Re: High esr miec electrolytic aluminum capacitors
PostPosted: Aug Fri 09, 2019 4:59 pm 
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Location: Annapolis, MD
ESR and leakage are caused by very different things---why would they be correlated?

Here's a Mouser search on general-purpose electrolytics. ESR values similar to what you cite don't seem to be unusual......so, why do you think there is a problem?
https://www.mouser.com/Passive-Componen ... acitance|0

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 Post subject: Re: High esr miec electrolytic aluminum capacitors
PostPosted: Aug Fri 09, 2019 5:30 pm 
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Location: 18424 PA
I wouldn't say it's VERY high, but somewhat high. MIEC aren't the greatest as are Illinois, they are both cheap. What voltage are you planning on running them at?


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 Post subject: Re: High esr miec electrolytic aluminum capacitors
PostPosted: Aug Fri 09, 2019 5:37 pm 
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Joined: Sep Sun 02, 2012 5:58 am
Posts: 146
Location: San Manuel AZ
Because leakage is associated with high esr.? I dont know how I come to that conclusion .or misconception. However, I am aware that new capacitors from respected companies like
Nichicon, can have higher esr than this. Isn't the object to have low esr? In most capacitors. Obviously, high esr is not associated with leaking caps. You are correct sir! However, doesn't high esr create heat and rapid
Deteriorating? And cause heat ,watts higher current?

Thanks for your feedback

Mike


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 Post subject: Re: High esr miec electrolytic aluminum capacitors
PostPosted: Aug Fri 09, 2019 5:37 pm 
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If they are used for power supply filters, I would be interested in the ESR at 60 or 120 Hz. If they were being used as caps inside a speaker system, I would care more about those high frequency results. You would not want to put a cap with an ESR of 6 or 11 in series with an 8 Ohm tweeter, I would guess. I don't know about your tester, but I just did a test on my Sencore to see how close the ESR is to reality. I zeroed out the leads and then connected resistors between .47 and 47 ohms and did the ESR test ONLY. The values on the screen were very close to the marked values. So if mine says it has a cap with ESR 2.5 ohms, I think I can trust it. I forget what frequency it uses for test but it may be something like 1k.

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 Post subject: Re: High esr miec electrolytic aluminum capacitors
PostPosted: Aug Fri 09, 2019 5:42 pm 
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Joined: Sep Sun 02, 2012 5:58 am
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Location: San Manuel AZ
The caps are being used in power supply filters. Low frequency. Old tube power supplies and 400+ volts
At 100hz they are 17 0hms esr using the de5000

What sencor are you using ?
Mike


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 Post subject: Re: High esr miec electrolytic aluminum capacitors
PostPosted: Aug Fri 09, 2019 6:12 pm 
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Joined: Nov Wed 30, 2016 7:35 pm
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Location: Sunbury, Ohio 43074
I’ve noticed some odd results testing large value caps on my D5000. Haven’t looked into it much since I don’t do it often and usually use the TO6 anyway

But as noted your readings don’t seem that far out of line.

If you want to experiment (I may some day when my pile of projects shrinks) buy a few expensive caps and see how close to their specs they test. For someone with too much time on their hands, rig up Alan Douglas’ ESR tester as a lab standard to compare

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 Post subject: Re: High esr miec electrolytic aluminum capacitors
PostPosted: Aug Fri 09, 2019 6:32 pm 
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Joined: May Tue 30, 2006 4:46 pm
Posts: 10282
Location: Santa Rosa, CA
1. For work that I care about, I buy caps with data sheets from Mouser or Digi-key.

2. In 90% of tube power supplies, I don't worry about ESR.

3. Most problems with hi ESR are related to the fact that someone tested for ESR and is now worried about it. It's like doing full body health scans. My doctor says they cause more worries and seldom find anything useful. ESR was important when I worked in Applications Engr. at Siliconix, mostly on 100KHz SMPS.

We had a member, Curt Reed, now deceased, who developed the best test for suspect electrolytic capacitors.

--Cut it out of the circuit
--Toss it into a metal waste basket
--If you hear a loud "clunk" sound, it is bad and should be replaced with a new quality brand cap

Rich


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 Post subject: Re: High esr miec electrolytic aluminum capacitors
PostPosted: Aug Fri 09, 2019 6:51 pm 
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mdm54 wrote:
Because leakage is associated with high esr.? I dont know how I come to that conclusion .or misconception. However, I am aware that new capacitors from respected companies like
Nichicon, can have higher esr than this. Isn't the object to have low esr? In most capacitors. Obviously, high esr is not associated with leaking caps. You are correct sir! However, doesn't high esr create heat and rapid
Deteriorating? And cause heat ,watts higher current?

Thanks for your feedback

Mike

It depends......(the engineer's universal answer...;) )

Basically, it goes like this:
power: P = I^2 * R
heat / temperature: depends on power, but also how something is mounted / cooled.

Suppose your 1st filter is giving you 10 volts (rms) of ripple, and the 1st cap is 30uF.
at 120Hz, Xc is 0.159/(120 *30E-6 ) = 44 ohms. So the ripple current is roughly 230mA, and the power is (0.23^2)*ESR = 0.5 * ESR
If the ESR is 5 ohms, then the power is 2.5 watts----the part might get a bit warm, but is not going to do anything dramatic.
The above is only approximate....to be more precise, you have to find the total Zc and use that to get the current

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"Voltage is fun to watch, but it's the CURRENT that does the work."


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 Post subject: Re: High esr miec electrolytic aluminum capacitors
PostPosted: Aug Fri 09, 2019 7:07 pm 
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Joined: Sep Sun 02, 2012 5:58 am
Posts: 146
Location: San Manuel AZ
That will work Rich! But, some of the old caps test out better than the new.There is a fella in Europe but I forgot his name that was an expert in old caps vs new. His consensus was don't through out the old for the new. I will find his link and post it.anyhow , his testing proved this.

Mike


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 Post subject: Re: High esr miec electrolytic aluminum capacitors
PostPosted: Aug Fri 09, 2019 7:19 pm 
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Joined: Sep Sun 02, 2012 5:58 am
Posts: 146
Location: San Manuel AZ
Rich ,That guy in Europe name is Emilio Ciardiello
From radiomuseum.org he has an excellent paper on old capacitors vs new.

Mike


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 Post subject: Re: High esr miec electrolytic aluminum capacitors
PostPosted: Aug Fri 09, 2019 7:27 pm 
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Joined: Sep Sun 02, 2012 5:58 am
Posts: 146
Location: San Manuel AZ
Mark , good math and explanation. However,
High esr= worse
Low esr = better in most cases.
Am I missing the object? All circuits should be engineered
For efficiency. Correct?
Except for circuits the have problems with low esr caps
In that case, you want high esr
Mike


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 Post subject: Re: High esr miec electrolytic aluminum capacitors
PostPosted: Aug Fri 09, 2019 7:55 pm 
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Joined: Sep Sun 02, 2012 5:58 am
Posts: 146
Location: San Manuel AZ
Barry, good capacitor and esr link to mousers. Seeing all those high esr capacitor ratings data
Makes me sleep better. .

Also your website is excellent. Your on the right track!
I will use this as a reference


Mike


Last edited by mdm54 on Aug Fri 09, 2019 8:01 pm, edited 1 time in total.

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 Post subject: Re: High esr miec electrolytic aluminum capacitors
PostPosted: Aug Fri 09, 2019 7:57 pm 
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Joined: Jul Mon 26, 2010 8:30 pm
Posts: 29054
Location: Annapolis, MD
Engineering is all about the art of "good enough". Once you have a parameter established---with appropriate margins---there is no benefit in making it "better". Very often, that "better" will cause some other parameter to get "worse". If nothing else, "better" wastes resources.

In the NASA world, there is a sacred mantra:
Better is the mortal enemy of Good Enough
More than once, I was party to removing from a project an engineer that did not understand this....

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"Voltage is fun to watch, but it's the CURRENT that does the work."


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 Post subject: Re: High esr miec electrolytic aluminum capacitors
PostPosted: Aug Fri 09, 2019 8:06 pm 
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Joined: May Tue 30, 2006 4:46 pm
Posts: 10282
Location: Santa Rosa, CA
Quote:
That will work Rich! But, some of the old caps test out better than the new.


Testing does not tell us everything.

Old caps are still old caps. Decades of chemical action and unknown chemical constituents do not make me feel secure. Caps are so small and cheap now, why not just use good, new caps?

Pix: during World War II, the US developed sub miniature tubes to use in proximity fuzes for anti-aircraft. German scientists concluded that one could not make a good tube that would survive 20,000 gs down a cannon barrel. US engineers concluded they could make a tube "good enough." The US had very successful, if crude, proximity fuzes. The Germans did not.

I am old enough to remember the early Apollo flights. My company, Westinghouse, supplied various components for moon missions. When I think about how crude that technology was, I cringe. But it worked! Look up PIND testing. Particle Impact Noise Detection. We used to test to find out if we could hear loose particles inside a transistor can.

Rich


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 Post subject: Re: High esr miec electrolytic aluminum capacitors
PostPosted: Aug Fri 09, 2019 8:07 pm 
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Joined: Sep Sun 02, 2012 5:58 am
Posts: 146
Location: San Manuel AZ
Good point Mark ! I should have been an engineer because my whole life us one big "good enough " lol

Good enough is why the shuttle blew up at nasa.

Mike


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 Post subject: Re: High esr miec electrolytic aluminum capacitors
PostPosted: Aug Fri 09, 2019 8:19 pm 
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Joined: Sep Sun 02, 2012 5:58 am
Posts: 146
Location: San Manuel AZ
Rich, the atom bomb was "good enough" it worked. They were all amazed at the first test !

The Russians were really good at good enough!

Mike


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 Post subject: Re: High esr miec electrolytic aluminum capacitors
PostPosted: Aug Fri 09, 2019 8:35 pm 
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Joined: Sep Sun 02, 2012 5:58 am
Posts: 146
Location: San Manuel AZ
Barry , I tested some 1% poly capacitors and the de5000 was dead on. So was my other cheapo $30 cap meter. However, the de5000 gives wrong readings sometimes
And I have to reboot. It's a computer. They all have to be rebooted sometimes. Nature of the beast.

Mike


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 Post subject: Re: High esr miec electrolytic aluminum capacitors
PostPosted: Aug Fri 09, 2019 8:40 pm 
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Joined: Nov Wed 30, 2016 7:35 pm
Posts: 8541
Location: Sunbury, Ohio 43074
Quote:
Better is the mortal enemy of Good Enough. More than once, I was party to removing from a project an engineer that did not understand this....

+12!! Left to themselves, engineering would never release something to marketing, because it can always be better. On the other hand, left to THEMselves, marketing would never allow engineering to finish a product to even the 'good enough' level. It's an eternal struggle, and why management needs to be well versed in BOTH engineering AND marketing.

Quote:
Good enough is why the shuttle blew up at nasa.

Not precisely ... that was a sad case of marketing overruling engineering with disasterous results. The decision was made to launch, in spite of the advice against it from those who knew that the O rings were too cold. Bad gamble, people died.

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Preserving the hist. of electronics, one boat anchor at a time! :)
https://www.bbtvtestequipment.com


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 Post subject: Re: High esr miec electrolytic aluminum capacitors
PostPosted: Aug Fri 09, 2019 8:51 pm 
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Joined: Sep Sun 02, 2012 5:58 am
Posts: 146
Location: San Manuel AZ
Barry, it was determined by someone at NASA to be good.
enough

Mike


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