DE-5000 Can I Trust Its Figures ? - Page 1
Forum section: electronics / testgear

author: DoDaMaffs
author_rank: Contributor
timestamp: July 31, 2014, 07:10:15 am
content: Dear Fellow De-5000 Owners,I recently aquired a DE- 5000 (not IET) and have been doing comparativemeasurements alongside the following DMM's in regards to resistance andcapacitance.Fluke 189Fluke 187Agilent U1272AThe resistance measurements across all meters are +/- bugger all %The capacitance (and this is my concern) readings on the DE-5000are a mile away from the other meters.I am only comparing the capacitor value for referance only, and I am fullyaware that the DMM's are testing at 30hz and the DE-5000 at 100hz(and I have tried other frequencies in both series and parallel)Also before you ask I have calibrated or nulled out the test leads on theDE-5000 (supplied tweezers & clips)I am asking anybody that may have one or more of the above nominatedDMM's only and a DE-5000 if they are able to assist with a referancemeasurement say for example on a 2200uf 16 volt capacitor for comparison.Not sure of any other way that I can use to confirm as to whether my DE-5000is faulty or within specs.Best Regards & Many Thanks...........Pete

author: Lightages
author_rank: Unknown
timestamp: July 31, 2014, 07:16:57 am
content: I don't have any of the mentioned meters but....Multimeters are no the best instruments to measure reactive components. That is why we have LCR meters. Now it is possible that your particular LCR meter is out of CAL, but probably not. You did not state the different values measured or if the multimeters all agreed.If all the multimeters agree within a few percent and the LCR is really out, then you might have some concern for the accruacy of the LCR meter. Unfortunately a large value electrolytic is going to show different values by a wide margin based on the measurement method and frequency. I would check the accuracy against the multimeters using something more like a 100nf film cap and see how far apart they are. I think you will find the measurements to be much more in agreement.

author: mzzj
author_rank: Super Contributor
timestamp: July 31, 2014, 07:22:38 am
content: Quote from: Lightages on July 31, 2014, 07:16:57 amHear hear!I was just writing pretty much the same story.I wouldn't be suprised if the difference is over 50% between your meters with large electrolytic.

author: DoDaMaffs
author_rank: Contributor
timestamp: July 31, 2014, 08:08:11 am
content: Thanks for you replies,Just getting together a comparison chart of the reading with a numberof value capacitors and please dont get me wrong i am not trying tocompare pizza's with pies in regards to the meters, I am trying todetermine as to whether the DE-5000 is faulty and initial testswere as follows:(Using same short banana plug to aligators clip leads on all meters)2200uf 16 volt electrolyticFluke 189 2.27 mf @30hzU1272a 2.23 mf @30hzDE-5000 1813 uf @100hz100uf 25 volt electrolyticFluke 189 97.01 uf @30hzU1272a 94.35 uf @30hzDE-5000 82.75 uf @100hzWill continue with some other values & leads.Thanks Pete

author: BravoV
author_rank: Super Contributor
timestamp: July 31, 2014, 08:12:16 am
content: Suggesting to redo the measurements again, but this time with "ALL" frequency ranges at DE-5000 to see the different results at different frequencies.

author: DoDaMaffs
author_rank: Contributor
timestamp: July 31, 2014, 08:22:43 am
content: The closest reading that i could get to the true value andto the DDM's was at 100hz.I may have to set up the Tek scope and function generatoras I have no other referance to gauge the DE-5000 LCR.And it's quite possible that the DE-5000 is in spec but I amnot sure at this point in time. (I dont like question marksover equipment)Regards Pete.

author: BravoV
author_rank: Super Contributor
timestamp: July 31, 2014, 08:27:40 am
content: Use polystyrene cap instead of electrolytic, if you want to compare between those cap meters, not super duper accurate though, but ball park number should be enough.It has very similar capacitance values throughout the test frequencies.

author: The Electrician
author_rank: Frequent Contributor
timestamp: July 31, 2014, 08:32:07 am
content: Quote from: DoDaMaffs on July 31, 2014, 07:10:15 amPost the results for several capacitors that you got on the various meters.

author: DoDaMaffs
author_rank: Contributor
timestamp: July 31, 2014, 08:46:25 am
content: If I had a mate that had an LCR I'd be Ok,They all have welders and plumbing tools(no use to anyone).I did search for hours prior to posting and couldnot find any useful info. Most of the tests werecomparing various LCR's and Bridges.Also I will find out what the test voltage being appliedby all of the meters is and as recommended try othertypes of caps.Thanks.....Pete

author: wraper
author_rank: Unknown
timestamp: July 31, 2014, 09:58:21 am
content: my DE-5000 @100Hz vs U1272A4.00 mf 4.232 mf4.40 mf 4.640 mf97.28 uf 100.xx uf (jumping depending of cable placement, length approx. 40 cm)some random film capacitor217.6 nF 217.2 nF

author: DoDaMaffs
author_rank: Contributor
timestamp: July 31, 2014, 10:13:16 am
content: Wraper your a champion,This is what I was after and am aware of valuevariances between manufactures.I am sorry guys but it's my night to cook dinner, and i'm in the shit already.Have just tested a 104K100 Polyester MKT non pole typeafter running a bit of emery paper and alcohol on the bananasockets on the DE-5000.100nf Poly (104K100 MKT)Fluke 189 103.5nfU1272a 103.56nfDE-5000 103.42nfVery happy with that result.I now have to go back and test the previous values to see ifthe cleaning had any bearing on those measurements,I think that my meter spits the dummy with higher values.Not done yet guys.Pete

author: DoDaMaffs
author_rank: Contributor
timestamp: July 31, 2014, 10:26:14 am
content: Wraper,If you dont mind, what were those caps poly, elec ?And also brand if electrolytic.Thanks Pete.

author: wraper
author_rank: Unknown
timestamp: July 31, 2014, 10:38:54 am
content: Those were electrolytic cap, brand doesn't matter much actually as different batch won't be the same. Good idea about poly cap BTW.560uf 4v sanyo:DE5000 U1272A560.0uF 563.7uFEdit:Tried the same sanyo poly with the same rating but taller size (likely older, all of them removed from dead notebook motherboards). Difference is about 15uf for those.

author: DoDaMaffs
author_rank: Contributor
timestamp: July 31, 2014, 11:08:30 am
content: Thought i should post the specs for those that don't have it.Also my 189 and 187 are almost the same reading,so I will leave out the 187.All meters have less than 2 hours bench work since new.I save these for special events and use lesser meters out in the field.Regards Pete.

author: torr032
author_rank: Regular Contributor
timestamp: July 31, 2014, 04:21:27 pm
content: DoDaMaffs, mine behaves the same. Bought it about one month ago from this seller:http://www.ebay.de/itm/171260782793?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l264947uf 100VUT61E: 45,65ufDER EE 100Hz: 42,16uf120Hz: 41,88uf1KHz: 38,83uf10Khz: 34,8100Khz: can't read at allusing SMD tweezers, almost the same behavior with the multimeter test leads inserted.

author: The Electrician
author_rank: Frequent Contributor
timestamp: July 31, 2014, 04:37:15 pm
content: DVMs don't measure caps the same way the DE-5000 does. DVMs apply a known current to the cap and time how long it takes for the cap voltage to ramp up a certain amount.While measuring your 2200 uF cap, monitor the cap voltage with a scope. You'll see a ramp of voltage; you'll probably have to turn up the gain on the scope and adjust the DC offset to get a good picture. You'll find that the repetition rate of the ramp is 1 or 2 hertz. This rate gets faster with smaller capacitors; with a .1 uF, I got a rep rate of 40 Hz. You can't really say that a DVM measures a cap at any particular frequency because it doesn't apply a single frequency sine wave excitation.The DE-5000, however, does apply a single frequency sine wave, so we can say that the measurement is made at a particular frequency.I find that my Fluke 187 usually reads high on large electrolytics. Here are results I got with 3 capacitors comparing a Wayne-Kerr 6440B, the DE-5000 and a 187. The W-K and DE-5000 measured at 100 Hz; the 187 measured with a ramp at whatever rep rate it likes:W-K DE-5000 18797.60 nF 97.60 nF 97.9 nF1.531 uF 1.532 uF 1.54 uF5341 uF 5320 uF 5650 uFI would trust the DE-5000 over a DVM.

author: DoDaMaffs
author_rank: Contributor
timestamp: August 01, 2014, 12:02:03 am
content: To The ElectricianI sincerely appreciate your advice and had read this elsewerewhereby the applied current and frequency of the DMM'swill vary according to the value of the DUT.Unfortunatly I dont have a Wayne Kerr in the workshop sndthe referance to the 30hz output in the capacitance rangeon the DMM's was to confirm that they are using the samemethod to test, other DMM's may use other applied methods.28 - 42hz was present from all DMM's unloaded in capacitancerange either from one meter to the other and later into thefrequency counter.Your submitted measurements will assist to determine as towhethet my DE-5000 is a keeper or is going on a journeyback to Japan.Best Regards and Again Thank You for Your Efforts.Pete.Oh, and a warning to anyone about to connect meters together,do not have both meters in capacitance range whilst linked asdamage may occur to either meter.I was very careful when doing this type of test and was awareof the potential risk, so one on frequency and one on caps only.Or better yet, do what I did to be safe and use a counter or scope.( this text should be in red, dont know how to do it. )Update;Re-checked the flukes on two other counters andthe test frequency does vary around 40 - 45 hzdepending on the input impedance of the counter.Not that these tests are relevant in any manner .

author: eliocor
author_rank: Unknown
timestamp: August 01, 2014, 03:07:37 pm
content: I think you are comparing apples with oranges...Have you taken a look to the specifications of the devices you are referring to?Fluke 187/189:http://assets.fluke.com/manuals/187_189_umeng0200.pdfAgilent U1272A:http://cp.literature.agilent.com/litweb/pdf/U1271-90010.pdfDE-5000:http://www.deree.com.tw/downloadfiles/28-eng%29DE-5000.pdfI think it can be a bit difficult to compare the reading of the 189 with the DE-5000.189 precision: 1% +-5countsU1272A precision: 1% +-2countsDE-5000 precision: 0.3% +-2countsEven the numbers you are reporting are "wrong": you have to take in consideration the precision of your instrument(s) and remove the digits that are lost due to the errors in the measurements.

author: wraper
author_rank: Unknown
timestamp: August 01, 2014, 03:41:11 pm
content: I suppose that difference is mostly caused by parasitic effects in electrolytic capacitors: dissipation, ESR, inductance... Which cause multimeters to read wrong because of the far prom perfect measuring method.As you noticed when measuring polymer capacitors difference becomes very small unlike when measuring regular electrolytic capacitors.

author: DoDaMaffs
author_rank: Contributor
timestamp: August 02, 2014, 01:58:36 am
content: Reply to Eliocor.I appreciate your findings, but you do not understand what Iwas trying to do, Wraper I think gets it.Example:The Electrician has a Wayne Kerr and takes a measurement.His DE-5000 is in agreement with that measurement.He takes a reading with a fluke 187 on the same componentand relays to me the reading of the fluke and the componentsrated value.So because I dont have a Wayne Kerr but do have a 187and a DE-5000 which I am questioning is intergrity onI should then be able to ascertain the accuracy of myDE-5000 within a few percent.I am only using the multimeters as interpreters likeexchange rates for currency.To date the DE-5000 is showing approximately -20%for electrolytics around 1000uf and about -35%for electrolytics around 4700uf based on the manufacturersmarkings.The DMM's are displaying figures closer to the actual realrating for caps in this range. So I am trying to establish anumber of things.1. Is my new DE-5000 out of spec.2. Is the DE-5000 not suited for electrolytic's above 1000uf.3. I fully understand that DMM's are not the best tool for measuring capsand that's why I purchased an LCR.For lower value capacitors electrolytic, poly's etc the DE-5000 seems tobe pretty well spot on, and I dont see anywere in the manual that saysthat this meter will bullshit to you for electrolytics above 1000uf.I dont know, maybe it is common knowledge, can someone guide me.Happy to Listen.....Regards.....Pete

author: DoDaMaffs
author_rank: Contributor
timestamp: August 02, 2014, 02:30:33 am
content: Furthemore,After some heavy reading on the subject of LCR's and capacitancemeasurement, the LCR's will show a value of the DUT closer to"Real Wolrd" conditions that the component will be subject toin circuit in relation to operational frequency.I dont give a stuff about what the component will or wont do incircuit. If I am building a power supply and the schematic calls upa 2200uf cap on I go to the rack and grab a capacitor and test itprior to installation and the value looks questionable what can i do.Now the LCR can give me what the DMM cant, and that is an indicationof the capacitors health but only if the LCR is in specification.Thanks Again....Pete

author: The Electrician
author_rank: Frequent Contributor
timestamp: August 02, 2014, 05:18:07 am
content: DoDaMaffs,The subject line of your thread is "DE-5000 Can I Trust Its Figures?"Why didn't you say something like "Fluke 187 Can I Trust Its Figures?"It seems to me that you trust the 187 and 189 more than you trust the DE-5000. Why is that?Apparently you don't have any reference capacitors. You are only able to compare readings of various instruments you have, and you seem to trust your DVMs. Why?

author: DoDaMaffs
author_rank: Contributor
timestamp: August 02, 2014, 07:20:58 am
content: This has nothing to do with the U1272A, 189 & 187 reading's,They can display "HELLO WORLD" for all I care.I have no other Calibration Refererce for the DE-5000for capacitance and can only get a guage on it's valueby using a third party reference.The common link between your measurements and minehappens to be the Fluke 187 as an intermediate value only.If you had a 100 meters of RG-6 and so did I then we could disregardthe multimeters altogether and compare capacitance reading's on the coax.Although the measurement would be of a low reading and that's not an issueas the meter seems to be behaving itself under 1000uf.Or we are on opposite sides of the planet and we each have a piece of string.You have a tape measure and a brick, I only have a brick, how long is my string.I tell you that my string is eight bricks long, and then you can tell me how long mystring is in metric or imperial. (The multimeters are the common link or the brick)Sorry If you misunderstood were I was going with this.Many Thanks.....Pete

author: omgfire
author_rank: Regular Contributor
timestamp: August 02, 2014, 07:53:30 am
content: Quote from: DoDaMaffs on July 31, 2014, 07:10:15 amDoesn't certification address such questions? You can ask your local metrology lab for verification service.

author: DoDaMaffs
author_rank: Contributor
timestamp: August 02, 2014, 08:12:59 am
content: To Omgfire,Yes I could get it verified somewere but the cost involved would be3 or 4 times the value of the meter.I did specify to the seller when I puchased it that it must be testedprior to shipping and am running out of time should I want to send it back.There have been thousands of these sold and I doubt very much thatit is faulty based on numbers and very few complaints from people.I have never needed an LCR before and only have the DMM's and comparitivereading's from other owners to compare to.Best Regards....Pete

author: The Electrician
author_rank: Frequent Contributor
timestamp: August 02, 2014, 09:44:43 am
content: Quote from: DoDaMaffs on August 02, 2014, 07:20:58 amWhy are you using the 187 and 189 as a reference for the DE-5000? Why don't you use the DE-5000 as a reference for the 187 and 189? I get the impression that you trust the 187 and 189 more than the DE-5000. Am I misunderstanding your posts? You haven't come right out and said that you trust the 187 and 189 more, but it sure seems to me in your previous posts that you are making the assumption that the 187/189 is more trustworthy.Obviously, you have to trust either the 187 and 189, or the DE-5000, to be your reference. Why have you chosen the 187/189 to trust?Quote from: DoDaMaffs on August 02, 2014, 07:20:58 amWhy do you think the DE-5000 is not behaving itself over 1000 uF? How do you know that it's not the 187 and 189 that are misbehaving over 1000 uF rather than the DE-5000?Quote from: DoDaMaffs on August 02, 2014, 08:12:59 amI guess I don't understand where you were going in your previous posts. You showed a discrepancy between the readings of a large electrolytic on the 187 and the DE-5000, and then seemed to think the DE-5000 might be in error. But now you say you doubt it is faulty. Does this mean that you think the 187 is giving a faulty reading on the large electrolytic, rather than the DE-5000?

author: DoDaMaffs
author_rank: Contributor
timestamp: August 02, 2014, 09:58:35 am
content: I tested for one example ten new 4700uf 35 volt electrolyticsDe-5000 showed approx 3600uf @ 100hzU1272a & 189 showed approx 4570ufI am guided by you as to which I should trustPeteThe third party reference is not the multimeters reading for the DUT at all,it's your Wayne Kerr or somebody else that has a DE-5000 and a multimeterthat I have. If your DE-5000 say's HELLO on a DUT and your Fluke 187 Says WORLDfor the same DUT. These two words can be collated and that is the data thatI can use because our WORLDs should be simular. I can then confirm if HELLOis being spelt correctly on my DE-5000.

author: DoDaMaffs
author_rank: Contributor
timestamp: August 02, 2014, 10:54:53 am
content: Does anybody get it, at all, please reply as I think I am going mad.

author: omgfire
author_rank: Regular Contributor
timestamp: August 02, 2014, 10:58:03 am
content: Suppose you are trying to check caliper (LCR meter) with tape measure (DMM) by measuring soft jelly bean (electrolytic capacitors, which aren't very stable). First: you will get difference, because caliper squeezes jelly bean. Second: if another person chooses different (harder) jelly bean, he will get less difference between LCR meter and DMM.By the way, low cost references for DMM are commercially available (like DMMCheck). Is there low cost, commercially available references for LCR?https://www.eevblog.com/forum/projects/reference-for-lcr-or-esr-meters/

author: BravoV
author_rank: Super Contributor
timestamp: August 02, 2014, 11:02:25 am
content: Quote from: DoDaMaffs on August 02, 2014, 10:54:53 amAre you looking for a morale support or sort of confirmation from this forum members that we agree that your de-5000 is faulty and needs to be sent back ?CMIIW

author: DoDaMaffs
author_rank: Contributor
timestamp: August 02, 2014, 11:08:55 am
content: Very Good soft jelly beans.If you have a 2000uf cap and measure it on a device and it shows 2000uf.And I have the same 2000uf cap and measure it on the same device in thesame manor on the other side of the world excluding differences in temperatureand air preasure. I would expect the reading to be within a few percent of each otheror am I mistaken.Thanks....PeteAnd yes thanks Bravo. I am trying to find out if it is faulty or not by comparison.

author: The Electrician
author_rank: Frequent Contributor
timestamp: August 02, 2014, 11:27:38 am
content: I notice that your measurements of film caps, rather than electrolytics, gave results that are well within the accuracy specs for the 187 and the DE-5000 for both readings. There's nothing wrong with your DE-5000.You might want to have a look at this thread:https://www.eevblog.com/forum/testgear/about-capacitance-measurement-with-dvms/

author: torr032
author_rank: Regular Contributor
timestamp: August 02, 2014, 11:41:37 am
content: It depends of the caps quality really.Old cap at least 30 years old FRAKO, W.Germany 10000uf 40V,ut61E: 10,6mfder ee 100Hz: 10,19mf; D: 0.155 ohmsSeems like modern manufactures makes caps that would show the correct capacitance on a DMM at freq 30-40Hz. For any freq above that they loose their rated capacitance rapidly. Old caps do behave much better.

author: The Electrician
author_rank: Frequent Contributor
timestamp: August 02, 2014, 11:56:45 am
content: DoDaMaffs, in another thread where I was offering to send people calibrated caps, Rufus mentioned:https://www.eevblog.com/forum/projects/reference-for-lcr-or-esr-meters/msg357416/#msg357416He's quite right. The old GenRad Digibridge meters depended for their calibration on a single precision resistor. I suspect that the DE-5000 is similar. There's probably a single precision resistor for the internal calibration.This means that if your meter reads resistors accurately, then it also reads capacitors and inductors accurately.So, a good check for the accuracy of a DE-5000 is simply to measure a good film resistor with your DVM, which should be able to give you .1% accuracy, and compare to the reading your DE-5000 gives.I just measured a .1% tolerance film resistor and my Fluke 187 read 1000.3 ohms. The DE-5000 also read 1000.3 ohms except at 100 Hz, where it read 1000.4 ohms. It is equally accurate when measuring capacitance.

author: The Electrician
author_rank: Frequent Contributor
timestamp: August 02, 2014, 12:05:13 pm
content: Quote from: torr032 on August 02, 2014, 11:41:37 amA DMM will not measure a 10000 uF cap at 30-40Hz. It will make the measurement at something like 1 Hz.The phrase "correct capacitance" isn't generally applicable to electrolytics unless the frequency of measurement is specified. The capacitance measured at 1 Hz will be different than it will be when measured at 30-40 Hz. See the thread I referenced above:https://www.eevblog.com/forum/testgear/about-capacitance-measurement-with-dvms/

author: torr032
author_rank: Regular Contributor
timestamp: August 02, 2014, 12:25:40 pm
content: Ok, 30-40Hz or 1Hz really does not matter, it is important that 99.9% caps were manufactured to show the "correct" capacitance on a standard multimeter. Strange the quality started to descends when the multimeters began to have capacitance measuring function.One thing that crosses my mind is that, that's why for such a long time quality pro LCR metters were so expensive so that an average electrician could not see what crap manufactures are selling to us as a quality components.

author: G0HZU
author_rank: Super Contributor
timestamp: August 02, 2014, 12:37:32 pm
content: QuoteYou can measure an electrolytic capacitor for capacitance and ESR (and SRF) using a dual channel scope, a resistor and a sinewave source (and a few simple sums).i.e. using technology available to electricians/hobbyists for decades.

author: torr032
author_rank: Regular Contributor
timestamp: August 02, 2014, 12:42:39 pm
content: Quote from: G0HZU on August 02, 2014, 12:37:32 pmI don't have a scope, but I saw on youtube it could be done. I really doubt in the past many of the hobbyist knew and were aware it could be done.Anyway that is not the topic of this thread.

author: eliocor
author_rank: Unknown
timestamp: August 02, 2014, 12:57:44 pm
content: Quote from: DoDaMaffs onTodayat 11:08:55

author: G0HZU
author_rank: Super Contributor
timestamp: August 02, 2014, 01:43:04 pm
content: QuoteI've not seen that youtube video but I guess my point is that the scope method can be used to check the capacitance and ESR of the 4700uF cap at 100Hz. It is limited by the accuracy of the sense resistor and also the ability to (accurately) measure the phase angle between scope channels but it can measure capacitance and ESR to meet realistic expectations.I like the scope method because it can show me the self resonant frequency of the component as well as ESR and reactance vs frequency.I normally frown upon cheap H/H LCR meters but the DE 5000 does look to be a decent meter. In a few years' time I suspect someone will offer a cheapo meter that can measure impedance across a sweep from LF to a few MHz and plot the results on a PC. i.e. in a similar fashion to the pro meters available today at much higher cost.

author: JuiceKing
author_rank: Regular Contributor
timestamp: August 02, 2014, 03:39:38 pm
content: I have the DE-5000, a Fluke 87V, and several LCR bridges. Testing a nominal 1000uF electrolytic capacitor on each gave varying results:DE-5000 (0.3% accuracy): 895uF/0.03D (1000Hz, Cp)HP 4260A (1% accuracy): 828uF/0.33D (1000Hz, Cp)General Radio 1650B (1% accuracy): 840uF/0.3D (1000Hz, Cp)General Radio 1608A (0.1% accuracy): 842.3uF/0.3D (1000Hz, Cp)Fluke 87V: 1021uFTest signal levels on the bridges were all between 0.5 and 1.0Vrms.I'm leery of the DE-5000 here. The dissipation factor appears to be off by an order of magnitude.The Fluke has consistently given high readings on electrolytic caps over the bridges.The very close agreement of the General Radio bridges makes me think that they are probably the most trustworthy. The 1608A is a high tolerance instrument that I've confirmed to be in calibration against reference standards not too long ago, but at lower ranges.- Ken

author: Retep
author_rank: Regular Contributor
timestamp: August 02, 2014, 03:43:01 pm
content: I have also noticed that for electrolytics the capacitance readings on my DE-5000 are significantly lower than the figures on the other meters in my possession that can measure capacitance. The figures on the DE-5000 are @1kHz about 20% lower and @ 100 Hz about 10% lower than the other meters.For example when measuring a 10µF rated electrolytic capacitor I see:DE-5000 @ 1 kHz 10.345 µFDE-5000 @ 100 Hz 11.166 µFNo name $15 LCR meter 11.20 µFMetex 3650B 11.78 µFVoltcraft VC 850 12.00 µFFluke 179 12.0 µF$20 transistor tester 12.13 µFIn this case the DE-5000 gets closest to the rated value, however with many other capacitors the DMM's are closer to the rated value.I don't see this difference with other non-electrolytic (< 1µF) capacitors, with those caps the meters pretty much agree with each other.The measurement frequency makes a big difference on the DE-5000, @ 100 Hz the readings get closest to the rated capacitance.

author: c4757p
author_rank: Super Contributor
timestamp: August 02, 2014, 03:57:54 pm
content: Electrolytics are very often significantly far off from their rated values, so closeness to the rated value is a quite useless measure of accuracy. They also suffer from horrifying shitloads of nonideal factors like dielectric absorption, meaning different measurement methods are almost guaranteed to yield widely varying results. No reason to suspect the DE-5000 is less accurate, it's just measuring differently. The "most accurate" method is just going to be the one that's most similar to how you're going to use the capacitor.

author: eliocor
author_rank: Unknown
timestamp: August 02, 2014, 06:11:21 pm
content: I really do not understand why some people measure electrolitic capacitors at different frequencies than 120 Hz (I was wrong...) like stated in their datasheets.just take a look at product from Panasonic:http://industrial.panasonic.com/ww/i_e/00000/id_almiec_e/id_almiec_e.pdfand you'll find that for every different type of capacitor is clearly stated the measurement frequency.So I'm asking to the ones who have made some comparative measurements:please redo the measurements with the correct frequency and discard the ones which are made with different frequencies (or at least clearly state that the measure was made in a different way than what specified by the producer).Using different frequencies can be useful to analyze the behavior of the capacitor (TanDelta, ESR, D, ...) but NOT for the capacitance value of the device!

author: The Electrician
author_rank: Frequent Contributor
timestamp: August 02, 2014, 06:42:24 pm
content: Quote from: JuiceKing on August 02, 2014, 03:39:38 pmA D value of .03 is much too low for a typical 1000 uF electrolytic. Are you sure you weren't measuring at 100 Hz rather than 1000 Hz with the DE-5000? Please redo, checking several 1000 uF electrolytics.I measured 15 different 1000 uF electrolytics with the DE-5000 at 1000 Hz, and the lowest D I got was .25; more typically I got .5 or more.Also, use Cs mode; that's more nearly what a DVM will get.Quote from: Retep on August 02, 2014, 03:43:01 pmWhat is the measurement frequency of all those other instruments? Do they all apply a sine wave excitation? Surely the Fluke 179 doesn't. It's to be expected that you will get different readings at different frequencies when measuring electrolytics, as I explained in the other thread.Would both of you please measure a large film capacitor with all of the same instruments; 10uF or more if possible. We know that measuring electrolytics can give varying results depending on frequency, excitation level (not so much, but can be a factor), whereas a good quality film capacitor should be mostly free of these effects. Note the good results I got with the 20 uF film cap in the other thread:https://www.eevblog.com/forum/testgear/about-capacitance-measurement-with-dvms/Also, measure a good quality film resistor of about 1000 ohms with a DVM to at least .1% accuracy, then measure that with the various instruments.

author: The Electrician
author_rank: Frequent Contributor
timestamp: August 02, 2014, 07:30:14 pm
content: Quote from: c4757p on August 02, 2014, 03:57:54 pmAbsolutely right!If a person wants two instruments to get the same measured value for an aluminum electrolytic, he must measure using the same conditions.The excitation must be the same; sine wave vs. ramp up method. Professional grade meters can usually vary the excitation level; this shouldn't be a source of variance with electrolytics, but will be with high K ceramic caps and with inductors.The measurement frequency must be the same; frequency in the case of sine wave excitation; duration and rate of the ramp up method. My Gossen Metrawatt gets a significantly different value than the Fluke even though both use a ramp up method--the Gossen ramps up slower, which is equivalent to using a lower measurement "frequency".Some low cost meters use an self oscillating circuit whose frequency is determined by the capacitor you're trying to measure. These meters may not be able to measure really big capacitors. I suppose the excitation may be a sine wave for some of them, but there are some that use a relaxation oscillator. In any case, the measurement frequency is not able to be fixed like the DE-5000; it is determined by the capacitor being measured.To show the level of agreement that can be obtained this way, even with electrolytics, I measured the same 1000 uF electrolytic I used in the other thread, measuring with the DE5000 and two high end meters. I set the two high end meters to have .6 volt excitation and 100 Hz:Instrument Capacitance DDE-5000 1166.0 uF .053W-K 1166.4 uF .052Hioki 1166.7 uF .052

author: engineer_in_shorts
author_rank: Regular Contributor
timestamp: August 02, 2014, 09:07:43 pm
content: Quote from: DoDaMaffs on August 02, 2014, 10:54:53 amYes we get it. You are going mad. Reply post 1 and 2 told you that you are not comparing like with like yet you ignore this.

author: wraper
author_rank: Unknown
timestamp: August 02, 2014, 10:06:41 pm
content: I suggest DoDaMaffs to get some conductive polymer capacitors like sanyo OS-CON, X-CON (samxon polymer brand), Nichicon LE or anything similar, just remove from a dead PC motherboard, whatever. Connect some capacitors in parallel to get about 2000uF of capacitance. Then measure, if difference between multimeters and DE-5000 will be less than 100-150uF, DE5000 definately is OK. If more, likely not. Suggest this as a cheap and ultimate way how DoDaMaffs can get piece in his mind.

author: G0HZU
author_rank: Super Contributor
timestamp: August 02, 2014, 10:17:47 pm
content: If you have a clean sine wave source (i.e. decent function generator?) and an accurate 1 ohm sense resistor and you want to measure a large capacitor at 100Hz then you don't even need a scope. You can use a DMM on ACV to measure the capacitance and ESR.I tried measuring a 1000uF cap at 100Hz three ways:The old school scope/VVM method (measure voltage and phase)Result: 929.8347uF ESR = 0.09829 OhmThe scope method (measure 3 AC voltages around the sense resistor)Result: 925.8267uF ESR = 0.09348 OhmThe DMM method (measure 3 AC voltages around the sense resistor)Result: 924.7735uF ESR = 0.09489 OhmI was quite impatient in taking the readings on the scope and a more careful tester would probably have got closer results. But I lose interest when trying for silly levels of accuracy on a dodgy device like a big old electrolytic capThe last method is the easiest and a DMM should be fine for measuring ACV at 100Hz with a decent sinewave.

author: DoDaMaffs
author_rank: Contributor
timestamp: August 03, 2014, 01:04:52 am
content: Dear Sir'sI was not seeking nor did I ask for an education on capacitance measurement.I was however requesting relative fiqures base on equipment that we both mayhave (189,187, U1272A and a DE-5000).A: A known constant (the rated value of your DUT)B: A known constant (the reading you get with your DMM)C: A variable value (the reading you get with your DE-5000)With A and B I can detemine if C is true or false (Good Or Bad)Thats All... Thank You

author: eliocor
author_rank: Unknown
timestamp: August 03, 2014, 01:19:45 am
content: Sorry, but your assumptions are bad:QuoteYou will never be able to extrapolate if C is true/false without knowing how to measure capacitance (and its pitfalls).You started wrong with your assumptions and you don't want to listen to people whose knowledge is much better than yours.

author: c4757p
author_rank: Super Contributor
timestamp: August 03, 2014, 01:25:01 am
content: Quote from: DoDaMaffs on August 03, 2014, 01:04:52 amI was not seeking a petulant retort, I was just contributing to a discussion on capacitance measurement, which is what it seemed like you were trying to start.

author: G0HZU
author_rank: Super Contributor
timestamp: August 03, 2014, 01:31:25 am
content: The reason I offered the DMM method is because the accuracy (at 100Hz) becomes a function of the accuracy of the 1R resistor (0.1%) and the accuracy of the DMM at 100Hz and the purity of the signal source.So this method provides a traceable reference that doesn't involve trusting/comparing the readouts on various LCR meters. You can also add a variable dc bias via the function generator and test the cap again to see if the capacitance is affected by the dc level.I've never owned an LCR/ESR meter because up until recently most of the low cost ones were complete shite. I'd include your Fluke in this category.

author: onlooker
author_rank: Frequent Contributor
timestamp: August 03, 2014, 01:32:09 am
content: QuoteIt is very confusing. The OP is doing a majority voting scheme (the A B C part)? but, does not really want other posters have their own votes?If the mind about the A B C scheme was already made, I guess the OP's purpose for this thread was to announce the finding that his DE5000 was inaccurate or defective, since other's tests were for different DE5000s and different caps.If the purpose was to ask others whether the A B C scheme is logically correct. The explanation will have to involve education about cap measurements.

author: DoDaMaffs
author_rank: Contributor
timestamp: August 03, 2014, 02:11:20 am
content: To All Posters,I would like to apologise to any members if I have in any way confused,misled or insulted by any comments that I have made.This is not my intention, and I greatfully and thankfully ackowledge all inputfrom all contributors.In addition, in the context of conversation some of my comments may beconstrued or interpreted as not only demeaning but as well as disrespectful,and again I couln't see it until it was pointed out, for this I am truly sorry.You have indicated that my propossed A B C method is unsuitable in determinigwhether my DE-5000 is at fault.Peter

author: wraper
author_rank: Unknown
timestamp: August 03, 2014, 08:31:30 am
content: Quote from: DoDaMaffs on August 03, 2014, 01:04:52 amThat's almost the same as if trying to determine with non true RMS voltmeters if true RMS one measures correctly without knowing AC signal waveform.

author: wraper
author_rank: Unknown
timestamp: August 03, 2014, 09:17:01 am
content: By that voltmeter comparison I mean: Get almost sinusoidal waveform (conductive polymer capacitors) to be able to directly compare them. As a capacitance by itself is not a sign of the electrolytic capacitor health (unless it's like half way off). ESR and Dissipation will tell much more. Just example: when repairing computer PSU, I desolder big electrolytic capacitors. They all measure good capacitance and equal ESR. But 2 of them have like 5x bigger dissipation factor than others. So it's a ring bell that they do not have too much life left in them. When they are almost dead, ESR also will be much higher. However capacitance will measure as normal until electrolyte completely dries out, usually device will start to have problems much sooner than that happens.

author: G0HZU
author_rank: Super Contributor
timestamp: August 03, 2014, 01:22:59 pm
content: Just to add credibility to the DMM + sense resistor method I used a Keithley 2015 to measure the sense resistor at 1.008 ohm using 4 wire sensing.I then used the 2015 as my ACV meter and fed a very clean 100Hz sine wave to the cap under test via the sense resistor and measured the 3 AC voltages around the sense resistor and put the numbers into a spreadsheet to calculate capacitance and ESR.I tested a couple of 1000uF 16V caps for ESR and capacitance individually and then tested them in parallel at 100Hz.The results for the effective ESR of the parallel pair the and capacitance were in agreement with the prediction calculations (based on the data from the individual caps) for having the two in parallel within about 0.5%.To calculate the effective ESR with two caps in parallel you have to convert each cap to its parallel equivalent and then work out the parallel model for the two in parallel and then convert back to series to get the ESR figure.eg the calculated/predicted ESR was 0.0500 Ohms and the measured was 0.0503 Ohms for the pair.The calculated capacitance of the two in parallel was 1850uF and the measured was 1845uF.If I'd taken more time over it and used a rock steady 100Hz source then maybe the result would have been closer. However, I would trust this DMM/sense method over comparisons between various low cost LCR/ESR meters because the whole process is based on simple theory and a few sums.

author: G0HZU
author_rank: Super Contributor
timestamp: August 03, 2014, 05:52:56 pm
content: I tried another cross check... I selected a 1000uF 16V cap and tested it first using a 1.008R sense resistor and measured the three AC voltages around the sense resistor. This time I also used a very accurate and stable 100Hz source with very low distortion. So essentially a pure sine wave at 100Hz.Then I tried again using a 2.720R resistor that was measured on the 2015 using 4 wire sensing. This method gives three totally different AC voltages around this 2.72R sense resistor at 100Hz but the spread sheet still gave the same results for capacitance and ESR.eg I got1.008R sense:Q= 17.39263349 d= 0.057495606SeriesRs = 0.09963 OhmsSeries Xs = 1.73288 Ohms918.0743 uF2.720R sense:Q= 17.44838932 d= 0.05731188SeriesRs = 0.09934 OhmsSeries Xs = 1.73339 Ohms917.4343 uFYou can see how close the readings areThis is because everything but the 100Hz signal is referenced to my Keithley 2015 with this method.The 100Hz signal comes from an Agilent sig gen referenced from a high stability OCXO.This method is NOT the crude scope+ function generator method used by various youtubers eg W2AEW or MJLorton.This accurate method is based on classic impedance measuring theory from any decent engineering reference book.It should be very, very accurate. Far too accurate for everyday use but a useful way to check the accuracy of a suspect LCR/ESR meter that also measures with a 100Hz sine wave?

author: WVL_KsZeN
author_rank: Regular Contributor
timestamp: August 03, 2014, 08:42:57 pm
content: I just measured a 2200uF electrolitic for you with a 187, 1272a, and DER-EE DE5000Fluke 289 : 2.02mFFluke 187 : 2.00mFAgilent 1272a : 1.965mFDER-EE DE5000 : 1.748mF @ 1KHzDER-EE DE5000 : 1.847mF @ 100HzAppa 76 RC-meter plus : 1.948mFI've no idea what frequency the Appa is using though (my agilent tells me it is measuring at 8Hz though.. it's measuring the DE5000 at 100Hz and 1000Hz correctly, so I'm guessing the Appa is not a real CR meter..)