What is better to use to determine the leakage of capacitors?  - Page 1
Forum section: electronics / beginners

author: tigr
author_rank: Regular Contributor
timestamp: September 21, 2017, 11:52:51 pm
content: What is better to use to determine the leakage of a capacitor, homemade tester, multimeter or transistor tester? It is interesting to know the opinion of experienced people. Perhaps someone has practical schemes for testing capacitors for leakage or loss.

author: VK5RC
author_rank: Unknown
timestamp: September 22, 2017, 01:24:12 am
content: There are a few simple capacitor leakage testing kits available for not crazy money , usually consisting of a boost switch mode high voltage generator and a milliammeter.You can get proper test gear that does it, including tests such as dielectric absorption. Note there are many different types of tests for capacitors, so you end up with a few different testers, eg conventional value tester, ESR tester, leakage. Some do 2 of these things but not all usually all.VK5RC

author: David Hess
author_rank: Super Contributor
timestamp: September 22, 2017, 02:49:52 am
content: A sourcemeter works well but since I do not have one, I use a power supply and multimeter. Below is a photograph where I tested some NOS solid tantalum capacitors of uncertain heritage.

author: bd139
author_rank: Super Contributor
timestamp: September 22, 2017, 05:51:58 am
content: I stack up all my linear bench supplies to get the max rated voltage for the cap and slide my shonky old fluke 8050 in series. Once it’s gone a few time constants, which is usually pretty fast as the source is very low impedance, it will settle at the leakage current.I wouldn’t use a switching boost converter as they seem to make the meter dicky for me as it’s measuring very low current.Really though I know what caps are likely to be duff and just replace them anyway.

author: tigr
author_rank: Regular Contributor
timestamp: September 22, 2017, 07:07:46 am
content: The difficulty of the problem is that the capacitor losses are of a different nature and they are all interconnected. By measuring poorly-functioning capacitors, it is sometimes difficult to understand the reason for its improper functioning.

author: tigr
author_rank: Regular Contributor
timestamp: September 22, 2017, 05:50:53 pm
content: Quote from: VK5RC on September 22, 2017, 01:24:12 amSuch a homemade tester I have, but there is only 160v. It seems to me that such a tester can see a certain leak, but it does not solve all the problems.Capacitor losses.http://www.sayedsaad.com/fundmental/12_Capacitor%20Losses.htm

author: BenKenobi
author_rank: Regular Contributor
timestamp: September 22, 2017, 06:47:21 pm
content: I'd look at a Heathkit IT-28 - it is on my shopping list - or something very like it. Depending what you're doing you really need up to 600V.Then you need to do the ESR measuring - but if it leaks to much before it gets to rated voltage it's a bin job.I spend hours on Mr Carlsons Lab (YouTube) - he has a lot of really good stuff on testing capacitors and insertion the correct way - i.e. outer foil to the shortest path to ground etc - but first you must find said outer foil - well perhaps I'm misquoting but something like that.Just stick this in your favourite search engine "mr carlson's lab capacitors"

author: PA4TIM
author_rank: Super Contributor
timestamp: September 22, 2017, 07:04:12 pm
content: My design goes up to 600V. Resolution 10mA to 100uA full scale. I use it a few times a week.http://www.pa4tim.nl/?p=1385Besides leakage I measure Capacitance and dissipation factor. These 3 thing will find almost every bad cap. If you really want to find every possible defect you also need an impedance analyser, do vibration tests and temperature cycling, and measure capacitance with a DC bias.

author: tigr
author_rank: Regular Contributor
timestamp: September 22, 2017, 07:41:46 pm
content: Quote from: BenKenobi on September 22, 2017, 06:47:21 pmIt is clear that in the capacitor all the losses have a certain connection with each other, but I noticed that this is not always connected with the ESR.3300uF/6,3v.

author: PA4TIM
author_rank: Super Contributor
timestamp: September 22, 2017, 08:10:39 pm
content: That is not the case for the toy on your pictureA cap has a impedance that is the combination of the resistance and reactance. The resistance is the real part, the reactance the imaginary partThe real part is also know as ESR and the ratio of the real and imaginaire part is the dissipation factor (DF). You can recalculate that to the loss angle (tan d) and the tangens from that is the DF (also known as D or 1/Q)So all are related. Leakage is given as a parameter in the datasheets.Besides a high ESR, to low capacitance, leakage, there are more defects like cathode rupture and dielectric absorption.Most defects are related to the oxide layer. That is the DC barrier and the source of the capacitance. Most defects are oxidelayer related.

author: tigr
author_rank: Regular Contributor
timestamp: September 22, 2017, 08:47:15 pm
content: Quote from: PA4TIM on September 22, 2017, 08:10:39 pmFor me, any toy that helps in the work has value.Moreover, the toy is properly calibrated.Could you make a circuit in a normal form and a printed circuit board?This kind of had a capacitor analyzer.

author: kripton2035
author_rank: Super Contributor
timestamp: September 22, 2017, 09:26:27 pm
content: here some capacitor leakage schematics : (change kripton2035 to kripton2035clone if you don't get anything in your navigator)http://kripton2035.free.fr/LCR%20meters/lcr-capaleakmete.htmlhttp://kripton2035.free.fr/digital%20esr/esr-sprut-de.htmlalso siliconchip made some leakage testers years agohttp://archive.siliconchip.com.au/cms/gallery/article.html?a=112073&i=8http://archive.siliconchip.com.au/cms/gallery/article.html?a=111934&i=8

author: tigr
author_rank: Regular Contributor
timestamp: September 22, 2017, 09:59:50 pm
content: At 100 volts there is a good circuit.http://www.epanorama.net/sff/Test_equipment/Meters/Capacitor%20Leakage%20Tester.pdf

author: Vtile
author_rank: Super Contributor
timestamp: September 22, 2017, 10:08:16 pm
content: Quote from: tigr on September 22, 2017, 09:59:50 pmActually from 3 to 100 volts. I have had that paper in my drawer for like 10 years now and the components are sitting somewhere deeply buried on my project box except the transformer, need to redesign the schematic a bit so I can get that project finally made. Thanks for reminder.

author: tigr
author_rank: Regular Contributor
timestamp: September 22, 2017, 10:25:18 pm
content: The most interesting thing is that I also have components for this scheme for a long time.Here everything is clearly visible. The capacitor has worked in the radio receiver for 40 years.1000uF/10v.

author: bjcuizon
author_rank: Frequent Contributor
timestamp: September 22, 2017, 11:08:44 pm
content: Have a look at this:

author: tigr
author_rank: Regular Contributor
timestamp: September 23, 2017, 06:58:17 am
content: Another good circuit is the capacitor leakage tester.

author: tigr
author_rank: Regular Contributor
timestamp: September 23, 2017, 07:57:50 am
content: The leak at the capacitors can be different. If it is large, then an analog tester is enough. But in many cases there is a hidden leak, which manifests itself only at the working voltage. In such cases, the analog tester will no longer help because of the low test voltage. However, there are also difficult cases when it is not possible to determine the leakage, but the capacitor does not work well in the circuit. In this case, the transistor testers are very useful.One has an additional parameter that determines how the capacitor holds the charge(Vloss). The other determines the voltage to which the capacitor is charged and to the breakdown(DY294).

author: PA4TIM
author_rank: Super Contributor
timestamp: September 23, 2017, 10:08:53 am
content: That is nonsens, my analog leakage tester goes to 600V and the advantage of an analog meter is that you see if it is constant leaking or pulsing (and close to going short) Digital or analog has nothing to do with the height of output. The leakage itself is analogThere is no hidden leak, it is just the oxidelayer that leaks. If that is locally to thin it will pass current while rebuilding the oxide. If the leakage is to high it heats up the layer, electrolyte vaporizes and without that the oxide layer can not recover. The thinner the layer the lower the minimum leakage voltage becomes.As far as I know the Vloss on your meter is no component parameter but a sort off "fault" of the meter, stated in the original design documentation. There is a huge topic about it.

author: tigr
author_rank: Regular Contributor
timestamp: September 23, 2017, 11:37:54 am
content: We do not know what happens to the capacitor in the circuit and how it behaves. Capacitance and esr can be normal, but it does not hold the charge at working voltage and therefore the power supply of the TV can not start.In addition to toy devices, I use adults up to 1000v.And I'm experimenting with something that is not being written about in big topics. In-circuit testing of capacitors for a leakage.Bad capacitor 470uF.

author: Spaghetti_142
author_rank: Newbie
timestamp: September 24, 2017, 02:24:13 am
content: A meter, measure the Farads/ufarads if there 5 to 10% low but alaways will be extremely low caps bad. There is a tester out there that takes t2 leads hookup one on each side and it has a speaker, short bleep good long bad.

author: tigr
author_rank: Regular Contributor
timestamp: September 24, 2017, 09:43:58 am
content: Quote from: Spaghetti_142 on September 24, 2017, 02:24:13 amIt's not very clear what you mean.

author: tigr
author_rank: Regular Contributor
timestamp: September 25, 2017, 09:59:55 pm
content: My capacitor leakage tester 0-160v.

author: VK5RC
author_rank: Unknown
timestamp: September 28, 2017, 11:22:02 am
content: Do you isolate the input 230V?Similar circuits often use a pair of standard 230 to 12V transformers back to back - to act as a cheap isolation transformer.

author: tigr
author_rank: Regular Contributor
timestamp: September 28, 2017, 06:26:09 pm
content: I did not have a separating transformer 220/220v. I put the 220 / 160v transformer in a well insulated box.Another simple scheme of capacitor leakage tester.

author: tigr
author_rank: Regular Contributor
timestamp: September 30, 2017, 08:40:35 am
content: Quote from: tigr on September 22, 2017, 08:47:15 pmResistor 0,01Ohm.A good capacitors.

author: Zero999
author_rank: Super Contributor
timestamp: September 30, 2017, 07:05:56 pm
content: For low leakage, fairly large capacitors, there's no need for a nano-amp meter.Charge the capacitor up to its maximum voltage.Leave it, with nothing connected to its terminals, for a known period of time.Measure the voltage, as quickly as possible, preferably with a meter which will take the maximum reading and hold. The input impedance of a 10M meter can be boosted by adding high value resistors in series with it and the actual voltage can be calculated, using the potential divider formula.Calculate the charge lost and thus the RC time constant and the leakage current.

author: tigr
author_rank: Regular Contributor
timestamp: September 30, 2017, 08:46:22 pm
content: Yes, this is an acceptable method. But only if we can not measure leakage by other testers. It is necessary to take into account the fact that leakage is more difficult to determine than ESR.The old proven method, which is still used by repairers, is an analog tester. The only limitation is the test voltage of 3v.

author: tigr
author_rank: Regular Contributor
timestamp: October 01, 2017, 09:44:35 am
content: As we can see, all ESR meters respond differently to a capacitor with a very strong leakage.