Very low and accurate inducdance and capactiance meter ? - Page 1
Forum section: electronics / testgear

author: lordvader88
author_rank: Frequent Contributor
timestamp: January 21, 2017, 04:37:21 am
content: I have a general purpose tester (based on M328 IC iirc) that reads resistors, diodes, transistors, caps, inductors, a few others, and to some degree ESR, but I don't think very accurately since so many small caps read the same. For the $20 price its nice tho and types of things it tests thats great tho.What kind of qUALITY METER TO i NEED FOR PICO Farad caps, and for nano Henry inductors (I guess pico Henry's sizes aren't used ?). And that also measures ESR/LCR ?And what is a typical ESR of pico and nano F caps ? My meter often says 18 or 22 Ohms. And most videos I see where ESR is tested, the values are always lower than what this thing says for average sized electrolytic caps. This thing is a poor ESR meter.

author: Ammar
author_rank: Regular Contributor
timestamp: January 21, 2017, 04:41:30 am
content: You can expect to pay thousands to measure down to picofarads. We have a potentiostat in our lab that we use to characterise implanted electrode arrays. That goes down to picofards and was $9000 for the unit and $7000 for the software license. They're cheeky like that.

author: kripton2035
author_rank: Super Contributor
timestamp: January 21, 2017, 07:48:54 am
content: this utiity meter was first designed to identify transistors. it was then extended to read resistors and capacitors, but was not designed at first to do that. so it does it quite bad. it even does quite bad the esr because it's not designed to do it in circuit, that is most of the utility of an esr meter... but it does very well identify transistors !about another meter: take a look at the deree de5000 :http://kripton2035.free.fr/LCR%20meters/lcr-deree5000-cl.htmlthe resolution of this meter is 1m?±1%, or 0.01pF±1.2% or 1nH±2.5% at best according to the manualit costs around $100 and has far better specifications than your tester.of course it won't compete with a $9000 dedicated instrument, but it's far better than what you're struggling with !if you want a nist certificate, you can get the original IET DE5000, but it will cost you around $1000

author: jpb
author_rank: Super Contributor
timestamp: January 21, 2017, 09:46:37 am
content: I have the DE-5000 and it measures down to 10s of pF but I'm not sure of the accuracy. It seems to do well.As examples, I have been fixing an HP10811 and checking some of the 1% capacitors.It measured the 510pF one at 506.7pFit measured the 430nH inductor at 435nHit measured a 62pF one at 61.82pFSo the above were all very close and believable.But it measured a 330nH inductor as 360nH so I thought the inductor was out and bought two new ones and they both measured 360-370nH so I think the meter might be out on this.Remember that bond-wires etc are approximately nH/mm so there is no point in trying to measure anything less than a few nH.The main thing is the measurement frequency. The DE-5000 will only measure up to 100kHz. Inductors in particular are measured by the manufacturers at several MHz (for low value ones) so, for example, when I was trying to measure the 330nH values I was doing so at less than 1/10 th the frequency I should have been using.

author: jpb
author_rank: Super Contributor
timestamp: January 21, 2017, 09:51:55 am
content: Quote from: joeqsmith on January 21, 2017, 09:38:11 amYour pictures brought back memories - I worked on MMICs in research in the 80s as a young engineer and I remember our lab budgetting to buy an 8510 system. The cost was roughly £500,000 (for the complete system) when my flat only cost £28000!I used to like the fact that everything was gold plated and all the ritual of performing the calibrations before each measurement. The calibration pieces came in a hardwood box with the HP logo engraved on it, I guess by a very fine router though I was told that it was laser cut.

author: Kleinstein
author_rank: Super Contributor
timestamp: January 21, 2017, 10:30:50 am
content: In the low pF range as well as in the < 100 nH range, parasitics get important - so even the best instruments need a well controlled position of the cables and shields and usually a null measurement without the DUT before.Even many simple DMMs with a capacity range have resolution in the 0.1 pF range, and accuracy is not that bad.ESR measurements at small caps does not make that much sense, as the equivalent circuit for those small caps is usually a different one. The more usual ways to describe those caps is with loss factor and maximum quality factor.

author: jpb
author_rank: Super Contributor
timestamp: January 21, 2017, 10:49:18 am
content: There doesn't seem to be much on the market between the DE-5000 at < £100 and instruments like:http://www.ebay.co.uk/itm/Keysight-Used-4285A-Precision-LCR-meter-75kHz-30MHz-Opt-001-201-301-Agilent-/172392110194?hash=item28235ed872which costs > £6000 even second hand!I suppose the best low cost option for the amateur would be a bridge.

author: adranp
author_rank: Regular Contributor
timestamp: January 21, 2017, 12:59:26 pm
content: I would like to know if anyone has field experience with either Agilent E4980A (or AL) or HIOKI IM3570 (or any from this series). I saw someone around here selling an HIOKI but no one did a comprehensive review on them.

author: chris_leyson
author_rank: Super Contributor
timestamp: January 21, 2017, 01:03:44 pm
content: Tektronix 130 L-C meter will do 3pF or 3uH full scale in it's lowest ranges.

author: BravoV
author_rank: Super Contributor
timestamp: January 21, 2017, 05:59:57 pm
content: Quote from: lordvader88 on January 21, 2017, 04:37:21 amAs many mentioned, when it comes to that accuracy or resolution for capacitance, inductance and impedance (resistance) , usually these measuring instruments are priced in 4 digits, most called bench sized LCR meter. Yep, they're bugger expensive.Apart from the hefty price it self, the probes or the probe's cabling themself become critical. Some came with expensive connector like Lemo and need quite low capacitance cables like PTFE coax.While ago I was lucky to score an used PM6306 RCL meter. It can measure resolution down to 0.1 pF, 100nH or 0.1mOhm with working frequency from 50Hz up to 1MHz, did a teardown ->PM6306 TeardownExamples of the measuring accessories needed for this kind of measurements, (courtesy of HighVoltage)

author: ez24
author_rank: Super Contributor
timestamp: January 21, 2017, 06:50:37 pm
content: Quote from: joeqsmith on January 21, 2017, 05:45:14 pmAdded you to the listHope "additional info" is okhttps://www.eevblog.com/forum/other-blog-specific/dd/msg1093983/#msg1093983

author: HKJ
author_rank: Super Contributor
timestamp: January 21, 2017, 08:44:20 pm
content: Quote from: lordvader88 on January 21, 2017, 04:37:21 amSomething like the Keysight U1733C (0.00pF and 0.00uH) or the DER DE-5000 (0.0pF and 0.0uH). If you want to go lower you will get into trouble with the test leads.

author: G0HZU
author_rank: Super Contributor
timestamp: January 21, 2017, 09:07:38 pm
content: Here's a measurement of a 3.3pF ATC 800B series capacitor on my VNA here. I'm measuring its properties up to about 3GHz.This is VNA data post processed in Genesys to show capacitance, ESR and Q etc. Alongside it is the official 2 port s parameter measurement data from ATC for this capacitor. You can see the VNA does pretty well and the small difference in self resonance will be down to strays in my 1 port test fixture. They used a 2 port fixture.ATC only provide data above 500MHz so my data starts at 500MHz as well. But by 500MHz the 3.3pF capacitor will measure closer to 3.5pF because of its stray inductance etc. You can see how close the measurements are for ESR across this frequency rangeMy results are shown in the red traces and the wiggly blue traces are from ATC's factory data for this capacitor.

author: cdev
author_rank: Super Contributor
timestamp: January 21, 2017, 09:31:54 pm
content: Does anybody know the various theories of operation of the meters?

author: TurboTom
author_rank: Super Contributor
timestamp: January 22, 2017, 12:23:11 pm
content: The Applent AT826 is a very good meter for the money. Resolution in the lowest ranges is 1nH / 1fF / 100µR. Readings are quite stable and comparison with "professional" (yet ancient...) gear (HP 4275A) shows remarkable accuracy.

author: kripton2035
author_rank: Super Contributor
timestamp: January 22, 2017, 01:02:16 pm
content: what is better in the at826 compared to the deree5000 ? that justify 3x the price ?

author: TurboTom
author_rank: Super Contributor
timestamp: January 22, 2017, 03:50:24 pm
content: Quote from: kripton2035 on January 22, 2017, 01:02:16 pmSince I haven't got first-hand experience with the EE-5000, I cannot tell for sure if there's a noticable difference usage- or accuracy-wise. I've got an AT826 and after that, we purchased two more at work since the engineers there were quite amazed by its performance. When I bought it, I got it at a bargain (< 300 USD) and the EE-5000 was more expensive than it's now so the difference wasn't that substantial.A few details to consider are the beautiful colour TFT display (okay, that's more like a gimmick but in my opinion, it makes using the instrument more enjoyable), the built-in rechargable lithium battery with the charger supplied, a full USB interface and programming instructions (the instrument can be operated completly remotely via PC) and one digit of reolution more than the EE-5000.This may or may not make a difference worth to spend more money. For the hobby user the price tag is probably of bigger importance but as soon as the "proper" PC interface is required, things change.

author: kripton2035
author_rank: Super Contributor
timestamp: January 22, 2017, 04:35:42 pm
content: I was talking about the deree de5000 that is available around $100.

author: jpb
author_rank: Super Contributor
timestamp: January 22, 2017, 05:09:40 pm
content: All this talk of LCR meters got me curious so I looked at a few.Here is a puzzle, the R&S (Hameg) HM8118.Farnell seems to list the same meter at two very different prices:First at £1716 + VAThttp://uk.farnell.com/rohde-schwarz/hm8118/lcr-bridge-230v-uk-eu/dp/1636919and again at £5,042.748 + VAThttp://uk.farnell.com/rohde-schwarz/hm8118-02/lcr-bridge-meter-bench-200khz/dp/2680044and in my history the price is listed as£1,598.00 EachThe more expensive one is listed as HM8118.02 but seems to have exactly the same specs - so what is there to justify a x3 factor in price??

author: PA4TIM
author_rank: Super Contributor
timestamp: January 24, 2017, 09:04:02 pm
content: I have an IET DE-5000. Perfect meter, I use it e very day. Still spot on.For serious work I have an Ex-GR standardslab GR-1620 bridge. It has aF resolution. Also some GR, Philips and HP standardsI build a fF meter just for the kicks. see:http://www.pa4tim.nl/?p=2929For small inductors a Boonton 63H with pH resolution.For a wider range or hard to measure components a GR-1608 these are almost bizar accurate.When frequency plays a roll I use a VNA (or GR-1603)Just for fun I have a Tek 130I have some more bridges. (HP, WK, GR, ESI) Good labgrade bridges are very accurate and if not messed up by a former owner they stay very accurate. The downside is their size and weight. Some need a separate detector and gernerator.And they are not beginner friendly. Most tools like this are made for lab use by a user with a sound knowledge about what he wants to measure and how to do that.If you think ESR is measured at 100kHz and you want to measure the ESR of very small caps. you are not the bridge user the manufacturer had in mindMeasuring inductors is difficult because of many many reasons.Most important, why do you want to measure so accurate. Most times if I need to measure pF or nH it is RF and then I measure at the frequency I need that capacitance or inductance (for instance in filters) Measuring at the extremes, there are many traps.

author: TimFox
author_rank: Super Contributor
timestamp: January 24, 2017, 10:29:34 pm
content: Quote from: chris_leyson on January 21, 2017, 01:03:44 pmA great advantage of the 130 L,C meter (what it says on the front panel of mine, although the manual says "L-C") is that you can build a shielded test jig in a metal box with coaxial connectors (UHF with teflon cable are nice) and easily null out about 75 pF of stray capacitance (coarse and fine null knobs) before connecting the unknown capacitor. Using duct tape to hold the cables and box rigidly to the bench along with the meter is a good idea.

author: lordvader88
author_rank: Frequent Contributor
timestamp: January 24, 2017, 11:55:50 pm
content: So why are they all so expensive ? And why aren't there a bunch of mid range knock off's for $100s of $ rather than into the $1000 s ?Wel I guess I won't worry about this anytime soon.

author: tggzzz
author_rank: Super Contributor
timestamp: January 25, 2017, 12:08:42 am
content: http://www.edn.com/design/test-and-measurement/4435414/Sub-picofarad-measurement-with-CMOS-inverters

author: stuartk
author_rank: Regular Contributor
timestamp: January 25, 2017, 12:49:06 am
content: There is also the BK 891. Maybe worth a look.http://www.bkprecision.com/products/component-testers/891-300khz-bench-lcr-meter.html

author: kripton2035
author_rank: Super Contributor
timestamp: January 25, 2017, 07:09:47 am
content: you also have this 0.01pF capacitor by roman blackhttp://www.romanblack.com/onesec/CapMeter.htm

author: BravoV
author_rank: Super Contributor
timestamp: January 25, 2017, 07:16:07 am
content: Quote from: lordvader88 on January 24, 2017, 11:55:50 pmMeasuring capacitance and inductance or impedance results are tightly related with frequency.Most low end hand held are merely max out from 100 Hz up 100 Kilo Hz.High end ones usually can do scanning from few Hz up to Mega Hertz range, and able to scan the DUT's impedance profile, this feature it self made these high ends differ from cheap handhelds.An example capacitance result from 4 digits priced LCR meter, courtesy of The Electrician.

author: lordvader88
author_rank: Frequent Contributor
timestamp: January 25, 2017, 05:28:19 pm
content: Quote from: kripton2035 on January 25, 2017, 07:09:47 aminteresting, would make a fun project

author: 1audio
author_rank: Frequent Contributor
timestamp: January 26, 2017, 06:24:36 am
content: Quote from: TimFox on January 24, 2017, 10:29:34 pmYou are overlooking its ability to shield elements you don't want to measure. It was originally designed for measuring inter electrode capacitance in tubes and CRT's. You can guard elements that would distort your measurement. For small cap values there is nothing like it. You can actually use a coax on the UHF connector as a sort of probe successfully in ways you would nexer think to work.The bridges are nice (I have 3 ESI Videobridges) but not so hot for really small values. The old Boonton bridges are good for RF components as well but a VNA does the same easier.

author: PA4TIM
author_rank: Super Contributor
timestamp: January 26, 2017, 06:34:25 am
content: Quote from: 1audio on January 26, 2017, 06:24:36 amDepends on the bridge, my 1620 has aF resolution, is that small enough ?The 1608 also has no problem with small values. Even my HP4260 can measure pF values without a problem. Most bridges I have, have a guard connection.

author: 1audio
author_rank: Frequent Contributor
timestamp: January 26, 2017, 06:41:52 am
content: Bridges are nice, high accuracy precision instruments. The video bridges have very low ranges and 6 digits for lots of resolution but for small parts values you need to switch fixtures or struggle with kelvin probes on tiny parts and really a PITA for "in circuit" stuff. Fine for sorting caps inductors and resistors. Measuring gate cap on a Jfet -not easy.

author: LaserSteve
author_rank: Super Contributor
timestamp: January 26, 2017, 07:49:43 pm
content: TI FDC1004 For caps and roll your own...Steve