What Do I need for testing capacitors?? - Page 1
Forum section: electronics / testgear

author: azigta
author_rank: Regular Contributor
timestamp: September 18, 2014, 02:36:42 pm
content: I know that probably this question has been asked in the past but I tried searching on google and didn´t solve it so I tought I could try here as this is the best electronics forum I know.I don´t have much money so I can´t really afford a good meter. The one I have, does the job well, but It certainly isn´t able to measure capacitors... Well , it is able to measure capacitors but for now I haven´t been able to measure electrolytic capacitors, as it only reaches 100uF, its aUNI-T UT50AI have been reading about esr meters, I saw Dave using one at youtube, and it seems to be what I need for testing capacitors, without having to desolder them.But here goes the question. Is an ESR meter capable of reading non-electrolytic capacitors?I want to be able to read different capacitors, not just electrolytic ones. For example in a Dave´s video he shows how he measures a non electrolytic capacitor that was supposed to be 223mf and it reads out 580mf and that´s the way he knows it´s bad. Would a ESR tester tell me if a non electrolytic capacitor it´s good?What do I need for testing a different variety of capacitors? For now the only thing I know, it´s that I need an esr meter xD Thanks

author: Fluxed Matter
author_rank: Regular Contributor
timestamp: September 18, 2014, 03:03:10 pm
content: Readthis. You might find it helpful if you are on a limited budget.

author: tggzzz
author_rank: Super Contributor
timestamp: September 18, 2014, 03:28:07 pm
content: Quote from: azigta on September 18, 2014, 02:36:42 pmWhy do you need to test capacitors?Answering that question will indicate which parameters are interesting, required range, required accuracy.

author: azigta
author_rank: Regular Contributor
timestamp: September 18, 2014, 03:41:04 pm
content: Quote from: tggzzz on September 18, 2014, 03:28:07 pmI want to be able to test capacitors for repairing power supplies and pc motherboardsI need to test capacitors because I usually repair pc motherboards and power supplies and sometimes there is no way to know if a capacitor is good. If it´s blown I replace it, and that´s all I can tell about a capacitor, but if there are not blown I don´t know if they are OK or not, So it would be great to have that esr in circuit meter to test all the capacitors in circuit without having to desolder them. But does it work for non electrolytic capacitors too?This year I might buy different meters, like an oscilloscope and a capacitor meter, but I don´t really know wich do I have to buy. For what I know, an ESR meter will be a good choice, because it can measure esr in circuit, but will I have to buy another meter for non-electrolytic capacitors?

author: Wytnucls
author_rank: Super Contributor
timestamp: September 18, 2014, 03:52:26 pm
content: We also need to know how many pesetas you're willing to spend on an LCR or ESR meter, to answer your question properly.

author: azigta
author_rank: Regular Contributor
timestamp: September 18, 2014, 04:15:19 pm
content: Quote from: Wytnucls on September 18, 2014, 03:52:26 pmhaha Spain doesn´t use pesetas since 1998, we use euro xD anyway, I was thinking about 100€ max (about 130 us$)

author: tggzzz
author_rank: Super Contributor
timestamp: September 18, 2014, 04:16:43 pm
content: Quote from: azigta on September 18, 2014, 03:41:04 pmAh, that's key useful information. What you need is:one significant figure accuracyin circuitwhich rules in/out a whole load of options.

author: azigta
author_rank: Regular Contributor
timestamp: September 18, 2014, 04:21:52 pm
content: Quote from: tggzzz on September 18, 2014, 04:16:43 pmWhat would you suggest for 100€ max? (80 british pounds) Would One meter test both electrolytic and non electrolytic capacitors and be able to test in circuit? O will I have to buy 2 separate testers

author: tggzzz
author_rank: Super Contributor
timestamp: September 18, 2014, 04:40:24 pm
content: Quote from: azigta on September 18, 2014, 04:21:52 pmI wouldn't suggest anything, since I've never had your requirements. You can search as easily as I can, and you can filter them against any other unstated requirements.

author: azigta
author_rank: Regular Contributor
timestamp: September 18, 2014, 05:26:58 pm
content: QuoteOk, then I´ll search on internet but I still don´t know if an ESR meter can also test non-electrolytic capacitors. Does anyone know?

author: SeanB
author_rank: Super Contributor
timestamp: September 18, 2014, 05:31:49 pm
content: Yes, ESR does not change magically between the electrolytic and non electrolytic caps. You probably woyuld be best to buy the $20 component tester mentioned on the forum, as a beginning. Does capacitors and semiconductors along with resistors and inductors quite well, at least good enough to check motherboards.

author: azigta
author_rank: Regular Contributor
timestamp: September 18, 2014, 06:05:02 pm
content: Quote from: SeanB on September 18, 2014, 05:31:49 pmyeah, I looked it up and seems to be exactly what I need xD It is a good component tester! it even tells you what the component is if you don´t know it! haha that is so good. Yeah I think I´m going to buy one of these. I hope I don´t have any problem with it

author: kripton2035
author_rank: Super Contributor
timestamp: September 18, 2014, 06:30:41 pm
content: for 100€ you can get a DerEE DE5000 that is considered here as the best ratio price/performance for a modern lcr meteryou will get capacitance AND esr measurments, and more than that resistors and inductances.details here :http://kripton2035.free.fr/LCR%20meters/lcr-deree5000-cl.htmlyou can get them at japanese ebay sellers.the $20 component tester above is very good for transistor testing, but not that good for capacitors

author: SeanB
author_rank: Super Contributor
timestamp: September 18, 2014, 06:49:28 pm
content: For most computer motherboard caps it will do, as you just need to be able to see if it is close to rated capacitance and the ESR is below the max level. If not then it is cactus in any case, no real need to see if it is 1200uF or 1202uF.

author: azigta
author_rank: Regular Contributor
timestamp: September 19, 2014, 07:14:49 pm
content: Quote from: kripton2035 on September 18, 2014, 06:30:41 pmwow, definitely that´s what I´m going to buy! It´s awesome. Thank you!

author: markce
author_rank: Regular Contributor
timestamp: September 19, 2014, 08:24:09 pm
content: A DerEE DE5000 will not work reliably in circuit, it uses a 1.7V p/p test signal.You'll have to desolder components first for accurate measurements.

author: azigta
author_rank: Regular Contributor
timestamp: September 20, 2014, 03:43:07 am
content: Quote from: markce on September 19, 2014, 08:24:09 pmI expected it to work in-circuit! well, then i´ll buy an esr tester that works in circuit. I saw a few that are as expensive as the derEE DE-5000 and they only measure capacitors esr in-circuit. I´m so sad that the DE5000 doesn´t work in circuit. It just looked so well xD Thanks for the info.

author: PedroDaGr8
author_rank: Super Contributor
timestamp: September 20, 2014, 04:48:26 am
content: Quote from: azigta on September 20, 2014, 03:43:07 ammarkce is not correct.The DE-5000 should be fine for almost any in circuit measurements (other than paralleled devices, in which there is NO way to measure those in circuit). While it is true th DE-5000 has a 500-600mV test voltage, this is the open circuit voltage. If you add any impedance to the test the voltage drops RAPIDLY. Many have used this device for in-circuit testing. There is a post listing the various voltages under test with some impedance. I will see if I can find it again, I am drawing a blank right now.

author: TMM
author_rank: Frequent Contributor
timestamp: September 20, 2014, 06:42:10 am
content: Yes, the DE5000 works fine in-circuit most of the time. Sometimes you will have to put it into manual mode because it can't decide what the dominant measurement is (L, C or R), but that is hardly a big deal since you need to put it into manual to measure ESR anyway.

author: kripton2035
author_rank: Super Contributor
timestamp: September 20, 2014, 08:02:38 am
content: Quote from: azigta on September 20, 2014, 03:43:07 amI use my de5000 most of the time for in circuit measurments. and it works fine.when it's not possible (many capacitors in parallel) you will have to desoldier the components one by onebut it would be the same with a special designed in circuit esr meter (I have some of them ...)Now that I have the de5000 I always use itthe only drawback that was found is that it has almost no protection for overvoltage so you must carefully discharge the capacitorsbefore measuring. If you're not confident with that you've better buy a specialized esr meter like the peak or bob parker that discharges.

author: george graves
author_rank: Super Contributor
timestamp: September 20, 2014, 08:29:12 am
content: Quote from: Fluxed Matter on September 18, 2014, 03:03:10 pmI've been meaning to read that thead...48 pages....good god!

author: markce
author_rank: Regular Contributor
timestamp: September 20, 2014, 01:18:50 pm
content: First, I did not say it can's work. It's obviously just not designed for it.Example, take a 1.5nF capacitor. Take a reading, then add a 1N4148 diode parallel and take another readingwith the DE5000, its way off. Any capacitance below roughly 1uF will cause the test signal to bias Si diode or transistor in parallel. It clearly does not work in circuit without limitations. The level of the test signal simply is too high (0.85V peak).Lack of protection is an even more serious problem.When used as intended it is a very accurate instrument for a small price. I like it a lot!

author: azigta
author_rank: Regular Contributor
timestamp: September 21, 2014, 09:42:31 pm
content: I´m very happy to read it works in circuit, it´s just so good looking and so good quality! definitely it´s been good to read it works in circuit. I´ll buy it soon , thanks!

author: Mr Simpleton
author_rank: Unknown
timestamp: September 22, 2014, 08:43:49 am
content: This one do have very good reputation.. .not the cheapest but seems to be *very* good at testing caps:http://www.peakelec.co.uk/acatalog/jz_esr60.html

author: TMM
author_rank: Frequent Contributor
timestamp: September 22, 2014, 10:08:30 am
content: Quote from: markce on September 20, 2014, 01:18:50 pmMaybe so, but it only happens when testing a capacitor which doesn't have a low enough ESR to drop the voltage across the test leads below the forward voltage of the diode.You can remedy the problem either by cranking the test frequency to 100KHz or placing a resistor in line with the test leads.