Just get a cheap (~$10) chinese M328 meter. Doesn't matter which one....they all test the same and will give you accurate ESR no problem. This one is just an example smile.amazon.com/HiLetgo-Multifunctional-Capacitor-component-Backlight/dp/B01MYU0QI3/ref=pd_sbs_328_3/136-1972966-9684162?_encoding=UTF8&pd_rd_i=B01MYU0QI3&pd_rd_r=a80f9dda-291e-44e4-b8d3-3b6a44c6e35e&pd_rd_w=J8byH&pd_rd_wg=Mbki6&pf_rd_p=12b8d3e2-e203-4b23-a8bc-68a7d2806477&pf_rd_r=2AXJP1WMRQGQJDMSMMGB&psc=1&refRID=2AXJP1WMRQGQJDMSMMGB They all use the same chip (STM328), no matter how cheap or expensive the meter is. They are cheaper than this on Ebay but you just need to wait for the slow boat from China.

Ever heard of a LCR Meter?

Get familiar with a good meter you trust an you can do more than just a capacitance test to get an indication of if it's leaking DC. ESR meters are good an all but your not checking EPR anyway. 👍

yes, I've just watched a video prior to this one where the guy uses the resistance setting on the multimeter to test a capacitor - the resistance should go up to a certain value then go to OL.

Yes!

Jerry D get an oscilloscope , not an esr

In circut testing can get to a point where ultimately a lead or more would need to lifted to eliminate reading parallel components. Keep in mind a two lead device only needs one lead free to isolate and evaluate. Both to replace, obviously

This specific instrument can measure ESR of any type of capacitor, starting from 0,1μF upwards. Normally we are interested for detecting problems related to electrolytic capacitors (of any type). The instrument of this video is the “blue ESR meter”.

The usual tolerance for caps is plus or minus 20% in reference to their nominal capacitance. Yours seems to be OK.

There is "stuff" that comes out when it does burst and depending on the capacitor it can be brown. Don't confuse it with glue that they uses to sometimes hold the capacitor down from vibrating on the board.

For testing leakage, you are right. Nevertheless ESR meters are still better, because your leakage test might be good but still much of the capacitance might be lost due to the dried electrolyte. And this can be detected by ESR meters!

Nope. A regular ohm meter does not test it at different frequencys.

The principal of internal resistance applies to all capacitors (and batteries as well).

This was just a demonstration to show that ESR can change with temperature and even worse with a bad capacitor. The freeze spray can have its purpose when trying to find a hard to find pesky leaky capacitors that is nested in with many other capacitors. using the a heating cooling method. Check out my dell ethernet switch repair. It maybe saved me hours from removing all the caps from the power supply and testing them individually. The unit would only fail when it was in a fairly chilly environment. I have rarely if ever seen it cause catastrophic failures from using it gingerly.

Kev31779 I understood your purpose but there were no cautions or warnings in your demo and there were a couple of unanswered "huh" type comments. Several others in my class ran across and asked me about it so I posted the caution. Not stepping on your toes just eliminating " I saw it on KZfaq so it must be ok always"

No problems here. I admit , sometimes I can leave out some details unintentionally on some of my demonstrations. Its is tough sometimes with a low budget production as is mine. I do my best to help educate the people that comment in my videos to fill in the gaps. Sorry for any confusion I may have caused. I do like that people ask questions and or even point out things I may have missed. Thanks

Saying you have a low budget production is not a correct reason for leaving out important information. Doesn't cost much to write down what you intend to say and check you have covered everything in a logical manner. Maybe go so far as writing a writing a script..

What important information did I leave out that you are you looking for and didn't find? There Is no way to explain everything in this "Capacitor testing basics, Don't use a multimeter here is why" video. If you were looking for a more advanced video in capacitors than maybe you should have skipped this "basic" video and watched a more advanced one. It's not my fault you came to a video that clearly stated capacitor testing basics. This video is more or less showing people like the title says, don't use a multimeter and explains very clearly why. I think was covered in very logical manner.

They usually don't check esr They use a regular multimeter . It's works but it's the quick and dirty way..

If it is a big electrolytic capacitor there, try to see if it can get charged. For that purpose, use a small 12 volt power supply (or a battery with the same nominal voltage) and apply power to the capacitor by connecting a small incandescent lamp in series with it, say 0.5 Watt. Then watch if the lamp stops glowing after some time. The best is to connect a volt meter across the terminals of the capacitor. If the voltage rises, the cap is O.K. If not, the small lamp will glow permanently. In order to discharge the cap, after testing it, just connect the small lamp across its terminals. It will glow for some time, until the cap discharges.

You can absolutely do that if you like but it is not always necessary.

+ANKABOUT THE BEST An esr meter would be better.

+Kev31779 OK thx for fast reply

Well, without a schematic you can't get the exact value unless it is a SMD electrolytic which would be marked. Sometimes in your last resort you can experiment with different values or find a similar circuit in the device that may be the same and measure the value from that. In some cases if you call the manufacture if you give them the part location the may be able to tell you what the value is. But that is always a gamble that they will have that information and or be willing to give it to you.

really.…..that's why surface mount technology is garbage throw away crap. Through hole rules and always will when its circuit boards....but the real electronics are point to point pre-printed circuit era......its serviceable

I would use a smd heat gun and go over the caps with it one just spending a couple seconds on each cap. You may notice a area might make it work momentarily. Then use the freeze spray can with a straw on each cap in the area to reproduce the problem. It the cap is not exploded or completely dead this could work.

@@The_Active_Region Thanks for the tip. It's gonna be a major project as there's so many to test. I'll try to follow your example and see if it works. Thanks for sharing.

​@@jonfreeman9682 did it work?

@@tbprofile1295 No luck for me but that doesn't mean it won't work for you. You should give it a try.

Both tests are correct. Nevertheless, using an insulation tester for testing high voltage capacitors is better, because it tests the capacitors near to their working voltage. This means that there are cases where testing with low voltage (I.e by using multimeter) the capacitor might have a problem not revealed, while it becomes evident when the test voltage is high (using a “megger”.

2st3r1x.files.wordpress.com/2008/12/2003esrchart.jpg

Thanks , Hope that helps out.

It will change a bit but within the specs in the data sheet if stated. When a cap has bad esr the temperature can effect it a lot more.

thanks a lot

Peter Riis seriously right? not very controlled "science" not showing the difference between the new vs old resistance rise when froze and or heated.

It's not simply new vs. old. There are specifications for temperature coefficient for electronic components, and they're different. The tempco specification is used when choosing parts for a design depending on how critical it is to meet operating temperature ranges; low tempco parts will generally cost more, so it's a tradeoff.

All electrolytic caps have the same reaction to low temperatures. This is the main factor that telecom equipment works unhappily in North or South poles of the earth. On the other hand no capacitor manufacturer recommends such thermal stress for their (commercial) capacitors evaluation. As for the cap shown in the video, characterized as faulty, I would say that nothing is wrong with it because a) the ESR value of this table refers to brand new caps and b) even at minus 45 Celsius of this spray effect this cap was still measuring 95μF, that is, much higher than the minus 20% of its (down) tolerance - rejection limit. This specific cap has not the proper specs to respond to the demands of a modern switching power supply, but is perfect for any other (analogue) circuit (where low ESR is not needed, like audio circuits or linear power supplies). Capacitor manufacturers recommend replacements when their caps reach either the double of their nominal ESR given in their data sheets or when their leakage current reaches (or exceeds) the value usually calculated by the formula: L.C (in μΑ) = 0.03 x C(μF) x W.V (= working voltage in Volts).

@@skydanison991 👍

I think that the time of making an interesting living by electronics repairs belongs to the past. Cheap Chinese products of our time are not worth it to repairs...

@@user-pz6cx8zf2y sad fact, your probably correct mate.

Yes, there are plenty of them.

You are right! There is no temperature testing for caps, supported theoretically, for their evaluation. On the other hand, electrolytic caps cannot work in deeply low temperatures. This is long ago known. The same is true for lead acid batteries. The available capacity to be exploited in feeding temperatures is much less than their nominal and below -50 degrees their use is impossible. The same phenomenon happens with electrolytic caps. It is a matter of electrochemistry.

JoeJ8282 ESR is not the resistance through the capacitor. Equivalent Series Resistance is a measure of the capacitor’s reluctance to charge and discharge, which will cause self heating in a large ripple current situations. It cannot be measured with a multimeter on Ohms, inspite of what several unqualified people regularly say on their amp repair channels.

Charles Shaw; That is good to know. I wasn't sure but I kind of thought so. (I really DO need to buy me a good capacitance meter with ESR test!) However, even though a simple multimeter ohms reading may not be a totally accurate measure of a capacitor's series resistance, (because of more complicated interacting factors), that ohms reading can sometimes give you a rough indication of whether or not an electrolytic capacitor is horribly bad or out of spec or if it's probably OK, because I've had to utilize that test before myself when trying to troubleshoot a power supply circuit or two... Unfortunately I cannot afford a true, good quality Capacitance Meter with a real and accurate ESR testing function at this time due to $$, so I have to utilize whatever I can wherever I can, so a multimeter test of "ESR" of a cap is the best I can do, even though I couldn't count on those readings to be accurate in any *specific* way, but only just in a *generalization* of overall condition.

@@JoeJ-8282 With a multimeter, the only test you can do on caps in general is the leakage test...

@@user-pz6cx8zf2y OK. (Also measuring their actual capacitance value, if your meter has that function, like mine does.) And so how exactly do you do that leakage test? What is the exact procedure, step by step? (I didn't know you could do that and I'd like to know how to do it.) Thanks.

@@JoeJ-8282 you use the Oms ranges of the meter. I prefer to do this test with an analog multimeter (because it shows better the "capacitor effect") but a digital one will do the job as well, especially if the instrument has bar graph facility. If you can lock the meter to a low range, is better for the test of high capacitance caps (because the test current of the instrument is higher in the low ranges). Anyway the procedure is: 1) You have the cap out of the circuit (discharged. If not, for small caps only, short their terminals momentarily before testing). For big caps, especially of high voltage, use a 10 Ohm / 5W wire resistor to discharge them rapidly. Avoid shorting them anyway. Shorting them reduces their life expectancy. 2) You connect the probes of the multimeter: red to positive of the cap, black to the negative watching what happens. 3) In the beginning, the (healthy) cap acts as a short circuit. The indication is close to zero Ohms. But rapidly, as the cap charges normally, the Ohms indication increases until the cap is fully charged through and up to the level of the test voltage of the instrument. The final indication on the display is I or OL (infinite), as it was before connecting the cap. Now, some people reverse the polarity of the probes repeating this step. The reaction should be the same as before. I don't use polarity reversal, but new shorting of the cap's terminals before repeating (for confirmation reasons) the test. 4) The healthy behavior of the cap, is to reach infinity when charging. If charging slows down (watch the speed of the process in the bar graph of the multimeter's display) and stops somewhere, with the instrument showing a fixed resistance, this is the leakage indication. 5) If you were, say, in the 2 kOhm range and the test was successful, then you need to increase the ranges up to 200KOhm. The result should always be infinity. You can also use auto range function, but this will take much time when the instrument enters the MOhm ranges. This is useless, because above 1MOhm the cap is considered healthy. With an analog multimeter, this test is very fast and clear using the Rx1KOhm range. If you ever use it, keep in mind that the polarity of the test voltage coming out of the instrument is reversed. This means, for proper connection of the cap under test, red probe to minus pole and black to the plus pole of the cap. The needle pointer should initially peg and then slowly sit on the infinity mark. If it stays anywhere else, your cap is leaky. I hope all is clear to you now!

Correct in every word!

Old radios costs 100 of units, TVs etc...

An ESR meter is a “must have”, no matter if one works on vintage radio or switching power supplies...It makes your life easy!

If your multimeter is analog, then yes, the needle initially goes to zero and then, when the capacitor starts charging, it goes back to infinite (open circuit) resistance.

Exactly!

Not the in service resistance, an ESR meter sends a 100khz signal through the cap as it measures it's "working" resistance. Instead of just the resting resistance like a simple multimeter would do.

This instrument can measure real resistors up to 100Ohms.

There is no need to do so when testing caps.

@@marlinnano9370 "Grounding" has no place in this test. "Discharging" the capacitor before measurements is the correct procedure, but it is quite another thing to grounding. This (discharging) should be done if one wants to work with the circuit immediately after power off. This is the only case where proper discharging of the high voltage caps is absolutely necessary. Whenever one works in a non powered circuit, no such a precaution is needed. The same holds true if one waits for some minutes, after powering off the circuit and before working again with it, as bleeder resistors or the circuit itself discharge rapidly the bulk cap(s) to a safe level. On the other hand this specific ESR meter, according to its specs, can tolerate D.C voltages of max. 25 Volt safely. It will ignore any remnant voltage across a cap within this range. This makes it possible to measure with it not only electrolytic caps, but also battery arrays for their internal resistance provided that one must be careful as to avoid testing near the above mentioned voltage limit of 25V...

Borja Gadofi Please read once again ( but carefully this time) my extensive answer...

Borja Gadofi I already answered that in advance in my last paragraph of the extensive answer I sent you. It ends with a clear answer to your last question! And my point is to help young people learn. Not to compete you. I had already a successful career in telecom electronics and don’t expect any additional confirmation about that through KZfaq comments...

@@marlinnano9370 No problem!

Search for component tester on Amazon to see some inexpensive testers that are very useful for measuring all types of components. They can display capacitance and ESR with the same measurement along with identifying and characterizing diodes, transistors, inductors, resistors, as well as caps.

ESR meters measure that parameter of capacitors in circuit. That’s why they speed up the repair process.

Yup.

Kwasje Titty

Some failed capacitors can literally leak electrolytes. That means the capacitor has failed both electrically and physically. The term leaky capacitors can also mean that it can leak DC voltage through the capacitor that it is supposed to block. This can cause major problems to the circuits that are DC voltage sensitive. Capacitors are supposed to block DC and pass AC In theory. As capacitors start to become leaky they get high ESR. They become more of a resistor than a capacitor in which currents that it is supposed to block it passes. Without getting to technical I Hope this helps out.

Kev31779 Yeah, I didn't know Caps were supposed to block DC and pass AC. ok got it Thanks I like Electronics, but it's hard to find classes that teach it in So Cal. What could you suggest to help ?

KZfaq is a great place to learn . The only thing is that you will have to piece together the information you find that is on here. Search for things like - electronics basics, getting started in electronics, what is ohms law, what is AD DC.how to use a multi meter. Stuff like that.