XJW01 Auto LCR meter review ($120 bench top LCR meter) - Page 1
Forum section: electronics / testgear

author: nctnico
author_rank: Super Contributor
timestamp: March 20, 2014, 08:46:34 pm
content: When looking for an LCR meter on Ebay I came across a cheap LCR meter for less than $120 including delivery. I couldn't help myself and bought it...SpecsR 0.0002 Ohm — 9.999 MOhmC 0.1 pF — 10000uF or moreL 0.01 microH — 1000 HD,Q 0.001 — 9999For capacitors and inductors it also shows Q, D (dissipation factor?), ESR and DC resistance. It can be switched between three test frequencies: 100Hz, 1kHz and 7.8kHz. It comes with cables to make a 4-wire connection to the 'component under test'. The mains cable looks like it is for Australia.First impressionAfter the unpacking the box (which came from Belgium???) I found a sloppy casing which wasn't even closed. The inside was filled with plastic wrappings from apples and pears. At the back it says 110V. A kit with screws and feet to close the casing is also included. A manual is missing though. A quick look at the inside reveals one of the leads of the transformer is damaged and the person who assembled the unit used lots of hotmelt glue. For a prototype it would be OK but not for a production unit. The casing is too floppy to close nicely.Does it work?One wonders... Over here we have 230V so I used a variac to get 110V. It started but the readings where not very stable and every time I pressed a button it crashes. One thing I noted was that the beeper sounded for longer or shorter periods before the crash. Maybe it loaded the power supply too much so I removed the beeper. This made things slightly better but still not perfect. After some measurements on the inside it appeared the power supply voltage was too low. Next to the connector to the transformer the silkscreen says 9V (AC). I only measured 6V (AC). So I cranked the variac up to 130V. This made the display brighter, stopped the device from crashing when pressing a button and caused the readings to become stable.I measured some inductors, capacitors and a few resistors. The values shown seem right. My Agilent DMM says the resistor is 5956 Ohm where the LCR meter measured 5954 Ohm. Because there is no manual it takes some time to figure out what the buttons do. There are 3 buttons called C, R and L but those don't switch between the measurement modes. The X button switches between the measurement modes (the default is AUTO in which it detects what kind of component is connected). The R and L buttons switches between display modes (to show imaginary resistance for example). The C button enters a self calibration mode. The Q button switches between an angle and a percentage (of what?). Furthermore the display shows the range and test frequency. The F button changes the test frequence and there is an M button which enters some kind of frequency adjusment menu.OverallWhen I saw it was 110V I ordered a small transformer and I'm definitely going to put it in. For the money the unit does what it should do. One interesting aspect is that most of the components are through-hole. I even spotted some CD4052 devices inside. On the other hand there are several SMD diodes on the component side and solder side. That seems a bit weird to me because it makes production more difficult then necessary.Photos:

author: Carrington
author_rank: Super Contributor
timestamp: March 20, 2014, 09:04:55 pm
content: Interesting!But no more specification? Basic accuracy, for example.Edit:Ok, 0.3%.http://easy-taobao.com/taobao/view/id/18077625596http://easy-taobao.com/taobao/view/id/22601240432Within a "economic" range, I like these two: AT825 and U822C.

author: nctnico
author_rank: Super Contributor
timestamp: March 20, 2014, 10:54:22 pm
content: One of the reasons I bought it was for the 4-wire connections so it can measure low resistance values accurately. I think I also want to modify it to be able to apply a DC bias.

author: quantumvolt
author_rank: Frequent Contributor
timestamp: April 21, 2014, 03:59:44 am
content: Any more experiences with this meter? I will buy one soon. Strange there is not more interest in it here - it is a real half bridge with phase detection (the Greek 'Theta' in the display):Not at all like all those PCBw/328+1602 and handheld devices from eBay. It uses the same I/V or Autobalancing Bridge principle as Agilent and the other bench top LCR meters ...The first post inhttp://www.crystalradio.cn/thread-231933-1-1.html- started by the 'constructor' "xjw01" - has a .rar-file with documentation, schematic and code. The thread - started in 2011 - is still alive in April 2014 - with thousands of posts on some 370 pages.Nice project to study. I might even learn some Chinese ...

author: Vgkid
author_rank: Super Contributor
timestamp: April 21, 2014, 04:19:06 am
content: I'm curious why they chose the 7.8khz frequency, It is not to far off from the usual 10K frequency.

author: echen1024
author_rank: Super Contributor
timestamp: April 21, 2014, 04:27:41 am
content: I can translate the schematic if needed... my Chinese isn't too rusty I hope.

author: SeanB
author_rank: Super Contributor
timestamp: April 21, 2014, 04:59:16 am
content: Because you can get it by dividing the crystal frequency down in a divider inside the chip, and it will have a 50% duty cycle. To get 10kHs means you have to load the prescaler with a non even number, and this gives a non equal pulse. If you use a 24MHz crystal you can get pretty close to 10kHz, but will have to change the prescaler value.

author: Vgkid
author_rank: Super Contributor
timestamp: April 21, 2014, 06:19:58 am
content: Thanks, I figured that they could use the micro to generate a range of frequencies.

author: BravoV
author_rank: Super Contributor
timestamp: April 21, 2014, 07:06:29 am
content: Unless its for educational or for the excitement in building it from the scratch, whats wrong with the popular Cyrustek based LCR meters ?Price wise imo are comparable and also the Cyrustek's based LCR performance is already proven.

author: dannyf
author_rank: Super Contributor
timestamp: April 21, 2014, 10:33:42 am
content: There is also a newer version based on stm32 mcu that goes to the all elusive 100khz.those are well designed meters, and the code is available if you want to modify it.

author: Carrington
author_rank: Super Contributor
timestamp: April 21, 2014, 11:31:25 am
content: 100KHz Version:http://www.crystalradio.cn/thread-373788-1-1.htmlI was unable to find the source code and full PCB.Original 7.8KHz (last version):http://www.crystalradio.cn/forum.php?mod=attachment&aid=MTQyOTk4Nnw0ZjhhN2RjOHwxMzk4MDc2NzAzfDB8MjMxOTMz(http://www.crystalradio.cn/thread-231933-114-114.html)http://www.crystalradio.cn/forum.php?mod=attachment&aid=MjAyOTUyMnxkZmViMTBhYnwxMzk4MDc1MDMyfDB8MjMxOTMz(http://www.crystalradio.cn/thread-231933-267-267.html)Other 7.8KHz (last version):http://www.crystalradio.cn/forum.php?mod=attachment&aid=MjIxMjc1OXxiNzhhOTY1Y3wxMzk4MDcyMTU3fDB8MjMxOTMz(http://www.crystalradio.cn/thread-231933-334-334.html)http://www.crystalradio.cn/forum.php?mod=attachment&aid=MjIxMjc2MHxhMGMwMWQ1NnwxMzk4MDcyMTU3fDB8MjMxOTMz(http://www.crystalradio.cn/thread-231933-334-334.html)

author: quantumvolt
author_rank: Frequent Contributor
timestamp: April 21, 2014, 06:12:56 pm
content: The schematic below - taken from Carrington's link in the post over - is not the same as the 'This?' that Carrington has edited away and replaced with a PCBUnless Carrington wants to be perceived as a poster whose information must be saved immediately because it can be gone the next time you want to take a look at it, I suggest Carrington reposts the schematic without the AD9850 (with link or whereabouts). Thanks.

author: Carrington
author_rank: Super Contributor
timestamp: April 21, 2014, 06:28:41 pm
content: Quote from: quantumvolt on April 21, 2014, 06:12:56 pmIt was removed because it is not the 100KHz version. I care about what I publish here.So respect please, if you want it, you have only to ask me.Anyway, look in attachments.Cheers,Carrington.Source:http://223.4.85.240/thread-20901-1-1.html

author: quantumvolt
author_rank: Frequent Contributor
timestamp: April 21, 2014, 06:37:21 pm
content: Thanks.

author: Hydrawerk
author_rank: Super Contributor
timestamp: April 21, 2014, 07:49:01 pm
content: Oh, I would prefer a Cyrustek based hand held LCR meter. Some of them also have 4-wire measurement.http://www.tme.eu/en/details/ax-lcr42a/lcr-meter/axiomet/#This one is very cheap and has no 4-wire measurement.http://www.gme.cz/multifunkcni-rlc-metr-cem-dt-9935-yellow-blue-p722-483https://www.eevblog.com/forum/testgear/cheap-lcr-meter-cem-dt-9935/

author: Carrington
author_rank: Super Contributor
timestamp: April 21, 2014, 08:01:31 pm
content: Quote from: Hydrawerk on April 21, 2014, 07:49:01 pmGood value for money ( by the way excellent seller):http://www.ebay.com/itm/DER-EE-DE-5000-High-Accuracy-Handheld-LCR-Meter-New-from-Japan-Free-ShIpping-/151122560024http://www.ebay.com/itm/DER-EE-DE-5000-High-Accuracy-Handheld-LCR-Meter-with-TL-21-TL-22-New-Japan-/161104294237

author: Hydrawerk
author_rank: Super Contributor
timestamp: April 21, 2014, 09:17:38 pm
content: It runs on a 6F22 9 Volt battery. AAA cells would be better.

author: Carrington
author_rank: Super Contributor
timestamp: April 21, 2014, 09:31:17 pm
content: Quote from: Hydrawerk on April 21, 2014, 09:17:38 pmWell, nothing is perfect, or to taste everyone.

author: kripton2035
author_rank: Super Contributor
timestamp: April 21, 2014, 10:28:46 pm
content: if this one is effectively open source, you can learn a lot from it ...that's not the case with all the cyrustek proprietary meters.

author: dannyf
author_rank: Super Contributor
timestamp: April 22, 2014, 12:08:51 am
content: QuoteThe hardware design is fairly ordinary, with the following exception:1) P2.0 related circuits: it shorts the two inputs alternately, to allow the integration of the signal + its 90 degree offset. I used the same approach in my ESR meter - my implementation is DC oriented and his is AC oriented. But both do the job well. This allows the construction of a synchronized detector inexpensively and elegantly.2) P1.5 - watch out for that,3) the firmware has an elaborate calibration process. It is worth it to read through the Chinese version.4) there are cases where the meter will fail, just like any other instruments.Overall, it is well executed. I would have hoped that some one would implement the Russian LCR meter (designed around a msp430) on a modern chip, like STM32F3 or KL25.BTW, the sine wave generation is done via a filtered square wave output. The chip used here is quite limited. The compromise here is that one filter has to cover a wide range.A better approach, on a mcu with multiple pwm channels, is to use separate filters for individual channels / frequencies. That can be easily done on a chip like PIC24F.

author: dannyf
author_rank: Super Contributor
timestamp: April 22, 2014, 12:17:02 am
content: QuoteIf you look at its PA0 / PA1 pins, that's where the magic happens - identical to my implementation on the ESR meter. They form a very effective synchronous detector.No need to use those pesky analog switches.

author: BravoV
author_rank: Super Contributor
timestamp: April 22, 2014, 02:56:47 am
content: Calibrating common handheld DMM at voltage or resistance is relatively easy with easily bought references, but for the inductor or capacitor at the inductance, capacitance or impedance part D, Q, Phase angle, ESR or DCR down to few mili ohm accuracy ?Just wonder if the owner for these DIY type needs to "struggle" for the 1st time calibration to get to similar accuracy compared to their cheaper commercial counterpart ? In a hobbyist/enthusiast perspective of course.

author: JacquesBBB
author_rank: Frequent Contributor
timestamp: December 17, 2014, 09:30:52 pm
content: Dear Nctnico,Can you tell me what is the approximate weight of the XJW01 ?I consider buying one and I am interested in the postage fare.ThanksJacques

author: wblackledg
author_rank: Regular Contributor
timestamp: July 09, 2015, 01:59:34 am
content: got mine today from ebay for $100 delivered.The Good : It came unbroken.The Bad : the chassis wasn't fit correctly. I had to unscrew it, open it up then fit it back together. real cheese job in finally assembly.The case is really cheap. Seems you have to open it up to take the bindel off if you want.It also came with a Euro AC plug. (not for US). I had to find an old PC plug, which seems to worksomebody took a soldering iron and melted 110v into the back. (I guess sharpies are in short supply? )I tested some high end audio Elan caps against it, and this crappy meterhttp://www.ebay.com/itm/new-Digital-LCD-Capacitance-Capacitor-LCR-Meter-Tester-Multimeter-20mF-200pF-/271874301855?pt=LH_DefaultDomain_0&hash=item3f4cf89f9fI have seemed to be closer to the spec uf than this thing did, but not by much.Does anybody know of a way to calibrate this thing?thanks.

author: wblackledg
author_rank: Regular Contributor
timestamp: July 09, 2015, 02:14:28 am
content: Quote from: JacquesBBB on December 17, 2014, 09:30:52 pmweighs about as much as a computer keyboard, but smaller. if you really want I can try and give you the actual weight.

author: dannyf
author_rank: Super Contributor
timestamp: November 26, 2015, 08:59:09 pm
content: QuoteNice project. A very innovative design.- Cx@K3 produces the voltage across the DUT; Cy@K3 produces the current through the DUT.- sine wave produced through pwm;- the most interesting part is OP07 and V1/V2 as a phase detector: I have used similar designs in the ESR meter. It is a digitally controlled phase detector without resorting to analog switches - the typical implementation.- I didn't look at the software but he must be doing some fairly sophisticated math there.- He used a 8051. With a faster chip, he can simplify the design considerably and go much higher in frequency.- the calibration procedure is a little bit too complicated. But the fact that it is implemented at all is a huge plus.

author: nctnico
author_rank: Super Contributor
timestamp: November 26, 2015, 11:13:34 pm
content: I'm starting to like this little critter more and more. The good old HP4274A I bought a couple of months ago could not match it's capability to measure low resistance (tens of milli-ohms). Too bad it only supports a few frequencies.

author: quantumvolt
author_rank: Frequent Contributor
timestamp: March 07, 2016, 03:05:59 pm
content: Remote 'comparison' of XJW01 with Hameg HM8118 (new, in calibration -https://www.rohde-schwarz.com/us/product/hm8118-productstartpage_63493-44101.html).... --- ...Since I saw the XJW01 meter on eBay, I knew I would buy one (https://www.eevblog.com/forum/testgear/xjw01-auto-lcr-meter-review-%28$120-bench-top-lcr-meter%29/msg429607/#msg429607).In general I like it a bit untidy, sloppy, dodgy ..., and I thought that if it is all junk I can always follow the safety seeking herd and buy a DE-5000 (I will buy that one too).I have now had it about a year or so. I have had a lot of fun. To make a long story short I have collected quite a few quality caps (+- 0.5% and a few better). I have built oscillators and Wien bridges using Vishay precision resistors and 2x Agilent 34970A (AC range, interchanged bridge legs with relays) and a precision frequency counter. And a lot of math and statistical estimation / regression. All to determine the 'real' value of capacitors - and hence the errors of my XJW01.When I thought I knew the errors (for 'all' ranges, values and temperatures) of this box, I put in this adhttps://www.eevblog.com/forum/buysellwanted/%28wtb%29-measurement-of-capacitors-%28from-calibrated-lcr-meter%29-%28paypal%29/.I got an answer from a very nice member here that has a Hameg (Rohde&Schwarz) precision LCR bridge at work. So I sent him the test caps to England and got the results back in email. Thanks a lot for his kindness.This comparison (3 weeks between measurements) of my XJW01 is anecdotal in the sense that it cannot in any way be generalized, but on a collection of high quality caps (180 pF to 33.3 nF - almost zero loss and almost zero temperature coefficient), my USD 99 (Best Offer) XJW01 meter was never more than 0.155 % off compared to the USD 1500+ Hameg lab instrument.

author: Carrington
author_rank: Super Contributor
timestamp: March 07, 2016, 04:47:35 pm
content: Does anyone know where one can buy this other?And how much it cost?Source:http://www.crystalradio.cn/thread-373788-259-1.htmlThanks.

author: happydad
author_rank: Contributor
timestamp: June 02, 2016, 10:48:20 pm
content: Can someone explain how the design calculates ESR? I assume that the actual V & I measurements give us impedance, which is not ESR. What am I missing?Thanks.

author: nctnico
author_rank: Super Contributor
timestamp: June 02, 2016, 11:16:45 pm
content: You can calculate the capacitance and resistance (ESR) from the complex impedance. Google 'lcr meter formula' and you'll find a document from HP.

author: happydad
author_rank: Contributor
timestamp: June 03, 2016, 02:17:50 pm
content: OK, so I am assuming that the generator is putting out sine wave so we can get phase information from reading back V & I? A lot is hidden in the software, and I'm still trying to figure out how you extract phase information.

author: happydad
author_rank: Contributor
timestamp: June 03, 2016, 03:09:56 pm
content: From what I've read, in order to separate out the real and imaginary components from what was measured, we have to multiply the V and I by the signal generator, at both 0deg and 90deg. For education purposes, where is that implemented in the attached schematic? If I were to do a brief walk through, we have 6th-order LC filtered DDS sine wave ac coupled and buffered generator driving the DUT. We then measure the differential complex voltage (and current) through TL084 opamps, gained up by 2 and rc filtered through 1kohm and 470pF, and then running it through a programmable gain stage, then another 3x buffered stage to another differential TL082 with PA0 and PA1 ports. Here is where I am not sure what is going on. Are we trying to flip the sign here? If so, it's 180deg and not 90. Maybe the 180deg flip is to get rid of the reactive component? Very confused. Please help. Thanks.

author: nctnico
author_rank: Super Contributor
timestamp: June 03, 2016, 04:10:34 pm
content: That schematic isn't from the XJW01 !This thread has some info on how an LCR meter works (an LCR meter actually has a lot of similarities with an impedance analyser):https://www.eevblog.com/forum/projects/impedance-analyzer-build-and-experiments/

author: timofonic
author_rank: Frequent Contributor
timestamp: June 03, 2016, 04:37:43 pm
content: I wonder why aren't there a DIY high end bench DMM. Are they so difficult beasts.

author: lukier
author_rank: Unknown
timestamp: June 03, 2016, 05:12:03 pm
content: Quote from: timofonic on June 03, 2016, 04:37:43 pmOur forum member Mickle T builds 6.5-8.5 digits multimetersSee herehttps://www.eevblog.com/forum/metrology/lm399-based-10-v-reference/msg589601/#msg589601andhttp://bbs.38hot.net/forum.I suppose going above 5.5 digits is not impossible with DIY, it is just very expensive. Aging the references, buying Vishay resistors in small quantities, implementing and testing multi-slope ADC and then in the end you'll need 3458A / SR104 / Fluke 732B / KVD to test the performance. So at this point it is much cheaper and easier to buy 6.5 digit meter, even a new one (e.g. 3446XA) or look for a second hand on eBay.

author: Vgkid
author_rank: Super Contributor
timestamp: June 04, 2016, 03:58:44 am
content: Running off memory. Remember we are talking about lcr meters. Which work rather easily if you break it down to a dimpler model. Lets use components in series. The basic portions to a auto balancing bridge, what almost all (digital)bridges use. To calc the unknown impedance compare the voltage on the unknown to the voltage on the known resistor. Using dome math, we can ratiometrically determine the the impedsnce on the unknown resistor(this scored me bonus kudos in my physics class). Then to calc the parameter(phase shift) we measure the timeit tskes for the waveform to either lead/lag/stsy the same. When compared to the reference resistor. Now talking components: when making precise(relatively speaking) with good resolution. The main things that need to be reasonably stable is the amplitude of the sine wave. If you tbink about this, since we are dealing with ratios, an lm399 is overkill. Heck the GR1689 used used a 3 terminal voltage(adjusted to 2.5v) feeding the 8-bit dac. Wich was filtered to produce the sine wave. This signal was thrn passed through a high speed aml(lh002) before going through the reference and thd dut. For the reference resistor you needed stability, and low tc. Some units used flatt mica eound pww resistors. The lower end genrads used those. While the higher end oned used s102's. The esi's and Wayne Kerrs used a similiar system. Though I know that it seems like every ESI unit used a rather complex csl procedure. With frewuency high end ocxo's are not needed. Most units used a plain xo. With either a msnual frequency adjust(if it even has one), or a frequency offset stored in memory 1689/93.* I can go into more detail if you guys want it.** Im tired, and on my phone, so ignore spelling/grammar issues.

author: nctnico
author_rank: Super Contributor
timestamp: June 04, 2016, 10:24:57 am
content: I also have some experience with building LCR-ish circuits and one of the parameters you forgot about is noise. Also even when using ratios you'll still need a known-good reference. In my case I used a 0.1% resistor to achieve better than 0.5% accuracy.

author: dannyf
author_rank: Super Contributor
timestamp: June 04, 2016, 11:17:32 am
content: QuoteThe instruments essentially measure sthe voltage across the DUT, and then the current through the DUT (via a I/V conversion).PA0/PA1 is a simple synchronous detector: I suspect that the mcu alternately shorts PA0/PA1 to ground and float to measure V's and then I's phase relative to the control signals on PA0/PA1. With that, you get the relative phase between V and I.I haven't looked at his code but I have used an identical approach myself on a LCR build with an AVR (AT90USB1286 to be precise). It is not very efficient btw and given the number of analog switches he is already using, it puzzles me who he didn't go down the route of a real synchronous detector route.

author: dannyf
author_rank: Super Contributor
timestamp: June 04, 2016, 11:19:58 am
content: QuoteWith a build-in 24bit adc, it can be done fairly easily with a mcu (C8051F350 for example).Using discrete parts, external adcs, it is beyond most people's capabilities if you want to go over 20-22 bits.

author: Yansi
author_rank: Super Contributor
timestamp: June 04, 2016, 12:05:21 pm
content: There have been a few threads about these chinese meters, or the principles of their functionality. I have also kindly asked a member Blueskull to make a translation. If you find the thread, there is the translated schematic. Might be interesting for you interested guys :-)

author: Yansi
author_rank: Super Contributor
timestamp: June 04, 2016, 12:09:36 pm
content: Sorry, I haven't refreshed the thread, when I was writing.

author: nctnico
author_rank: Super Contributor
timestamp: June 04, 2016, 12:46:42 pm
content: Quote from: dannyf on June 04, 2016, 11:19:58 amYou don't need that kind of ADC resolution. The input frequency is fixed so crank up the gain of the measured signal enough to get to a reasonable ADC resolution. IIRC I used 500x in my circuit to measure in the tens of milli Ohms range using a 10 bit ADC in a microcontroller. At some point noise and non-linearities bite you in the ass.

author: dannyf
author_rank: Super Contributor
timestamp: June 04, 2016, 01:36:14 pm
content: QuoteThis version, built around a 8051, differs from the STM32 version posted earlier.1) the 8051 version uses a square wave + filter to generate the excitation signal; the STM32 version uses a dedicated DDS chip;2) the 8051 version has a dedicated AFE, the STM32 version reuses the AFE for V and I;3) the 8051 version has a different way of shorting the input signal in the phase detector.Overall, I think I like the STM32 version better. I do wish it had the AFE of the 8051 version.I suspect the STM32 version is newer.

author: nctnico
author_rank: Super Contributor
timestamp: June 04, 2016, 02:18:01 pm
content: I would like to have the newer version as well since it can go to 100kHz. Having the source code would be excellent; I assume it will be easy to let it make frequency sweeps so you can also use it as some kind of impedance analyser.

author: dannyf
author_rank: Super Contributor
timestamp: June 04, 2016, 03:38:52 pm
content: Here is how the phase detector works, in a nutshell.By alternatingly shorting the input to ground, here through two switches and in the xjw lcr meter through two pins (PA0/PA1 in the STM32 version, K7 and P2.0 in the 8051 version), you are essentially controlling how the two rc filters are going to be charged up.The output trace is the differential voltage between the upper rc filter and the lower rc filter. Traces are plotted with the input signal in 45 degrees apart, starting from 0 degrees at the top.The traces are just as you would have expected.So in his program, I assume he is using this approach to measure the phase differential between V and his reference signal (that drives the shorting of the input signal), and then measure the phase differential between I and his reference signal. Once you have the two, you get the phase difference between V and I.

author: Vgkid
author_rank: Super Contributor
timestamp: June 04, 2016, 07:37:23 pm
content: Quote from: nctnico on June 04, 2016, 10:24:57 amYou do need relatively stable resistors for that. In my .1% gr1658, 0.02% resistors are used. When it comes to higher end/ more advanced lcr meters. The internal resistor reference is not as important, ,but the stability is. For those, you calibrate them using a known external standard.+|- 10ppm for the 1689/93. With a known dq value to be entered as well.

author: happydad
author_rank: Contributor
timestamp: June 04, 2016, 09:34:36 pm
content: Hi Danny,Thanks for the sim on synchronous detector. I speculate that he is switching between PA0-high/PA1-low and PA0-low/PA1-high at 1/4 the signal rate, thus producing 0 and 90deg sampling of both voltage and current for a total of 4 readings. That will give you all you need to know about ESR and C. Sounds about right?

author: Yansi
author_rank: Super Contributor
timestamp: June 04, 2016, 09:45:44 pm
content: Yes, you measure the voltage and currect accross the DUT, both as complex variables (in phase and quadrature), so you can use the standard formulas for complex impedances to calculate any impedance.

author: happydad
author_rank: Contributor
timestamp: June 04, 2016, 09:54:43 pm
content: OK Thanks. So to recap, I am picturing sine waves of V and I that are 90 degrees apart right up to the synchronous detector. After the synchronous detection, there is an rc filter at 16Hz? Isn't that a little low?

author: Yansi
author_rank: Super Contributor
timestamp: June 04, 2016, 10:06:17 pm
content: No no... The V and I measured accross the DUT is not 90 degree apart, the phaseshift of those is defined by the impedance of the DUT at the tested frequency.Up to the synchronous detector, you have two analog signals, theoreticaly sinewaves. You will then need to measure how those two are phase shifted each apart (and what is their amplitude). Because also the voltage may be (and is) shifted a bit against the source (DDS output or any other generator of the sinewave test signal), you have to measure both V and I and take the phase difference between them.Lowpass? That is exactly right. The result of the synchronous detection is a DC voltage (look at the dannyf's diagram). If you feed the synchrodetector with an in-phase modulation, you will then integrate the magnitude of the real value Re{V} or Re{I} on the DUT. If you feed the reference as a quadrature, then the detected value will be the magnitude of the imaginary part, Im{V} and Im{I} respectively.As a result, you have measured both V and I accross the DUT, both as a complex values. It is then simple matter of the ohms law to calculate Z = V / I (in complex math of course).

author: dannyf
author_rank: Super Contributor
timestamp: June 04, 2016, 10:22:48 pm
content: QuoteNo. He is measuring the relative phase angle of V vs. the reference (switching) signal (PA0/PA1), and then I vs. the same reference signal.From that, it is easy to get the relative phase between V and I.

author: dannyf
author_rank: Super Contributor
timestamp: June 06, 2016, 11:06:19 pm
content: A big part of the complexity, in both models, is rooted in the desire of using and reusing cheap parts, as in thee form of fixed gain amplifiers, mcu control of gains, single sync detector forr both channels, etc.I think if I were to build one today, I would use two sync detectors, four adc modules, pgas, touch screen, etc. This would have greatly simplified the design.

author: happydad
author_rank: Contributor
timestamp: June 08, 2016, 01:24:46 pm
content: In the synchronous detector, are we alternately sampling half of the sine wave? And the integrators (low-pass filters) filter the output to give us DC values? I'm still trying to grasp the concept of synchronous detectors. Thanks.

author: Yansi
author_rank: Super Contributor
timestamp: June 09, 2016, 09:30:05 am
content: The basic principle of the synchrodetector is to multiply the incoming signal with the reference one. It's a basic math with goniometric functions: Multiplying two sinewaves with the same frequency leads to a dc component in the result (also dependent on their respective phase), however multiplying two with different frequencies leads to zero DC component. The DC component is what you get on the output after filtering. Therefore it is telling you, how much amplitude has the synchronous frequency present in the input signal.you can try have some fun in a math tool (at least wolframalpha.com) to see, what the dc result is, if you multiply your reference sin(t) or cos(t) with some harmonic input signal.For example, if your input is sin(t-pi/2), you will get zero in-phase (sin(t) reference multiplied) result, but maximum quadrature (cos(t) multiplied) result. From the two resulting DC components (in-phase and quadrature), you can easily tell, what amplitude does the input synchronous wave has (module of the vector, sqrt(I^2+Q^2)) and whats the phase difference between the reference and the input: tan(phi)=Q/I.The chinese meter uses somewhat simplified technique, multiplying the input only with a +1 or -1, like only the sgn(sin(t)) or sgn(cos(t)) references. This technique is cheap, easy, but somewhat shitty and deprecated these days, where you can get cheap enough MCU with enough grunt to sample both inputs (V and I) at 1Msps or so and do the multiplications and integration in real time.

author: Wh1sper
author_rank: Regular Contributor
timestamp: April 30, 2017, 09:51:09 am
content: I purchased this LCR Meter lateley.https://www.banggood.com/DIY-Auto-LCR-Digital-Electric-Bridge-Resistance-Capacitance-Inductance-ESR-Meter-Kit-p-1113600.htmlI'm very pleased with it, the price is awesome!I found a bit more of information about the usage, I think I'll try to brush up it a bit and put it on my Homepage in English and German.

author: Specmaster
author_rank: Super Contributor
timestamp: May 01, 2017, 01:10:29 am
content: Quote from: Wh1sper on April 30, 2017, 09:51:09 amI brought mine a few months ago, already assembled from herehttp://www.ebay.co.uk/itm/Auto-LCR-Digital-Electric-Bridge-Resistance-Capacitance-Inductance-ESR-Meter-New-/181367473225?hash=item2a3a580449:g:UogAAMXQeKNTOh0cand I must say that I'm very impressed with its accuracy but not so its manual, or should I say lack of a manual, so any extra information on this would be most welcomed by many of us on this forum.

author: Wh1sper
author_rank: Regular Contributor
timestamp: May 01, 2017, 02:55:03 pm
content: My German Article is in a first shot state, who can read German is welcome to comment for suggestions.http://zockertown.de/s9y/index.php?/archives/1672-LCR-Auto-Meter-Digital-Bridge-XJW01.htmlHere comes the automatic Google Trans of the chinese Description, which was my input for the German Article.Quote

author: Radiohead
author_rank: Contributor
timestamp: May 14, 2017, 09:54:44 am
content: I found the translated schematic by BlueSkull in this threadhttps://www.eevblog.com/forum/projects/chinese-lcr-meter-schematic-with-stm32-questions-can-someone-translate-please/msg832297/#msg832297and the ebay hardware kit almost 1:1 copied into an Indian paper, published on 3 October 2016:http://ijiet.com/wp-content/uploads/2017/01/18.pdfwhile search for RLC meter designs. Of course no references to either of them.

author: WhichEnt2
author_rank: Regular Contributor
timestamp: June 23, 2017, 11:41:17 am
content: Can anyone tell me about the 2.7MOhm parameter (attachment)? Avaliable docs are not clearly describe this.

author: buildafriend
author_rank: Newbie
timestamp: June 13, 2018, 03:17:01 pm
content: I just purchased a new one of these XJW01 meters. It came in a pretty robust metal case and seems to have gotten cheaper. It has undergone "some" evolution but seems to display the same things on the screen as what I've seen online. I got it for $80 including shipping. I want to thank you all for sharing this information. This is not a normal approach for finding technical information on a product. It seems to be somewhat scattered about and being translated in many different languages. I was about to throw the manual up here via google translate for everyone but Wh1sper beat me to it. Thanks Wh1sper and the OPOkay soo..there's a menu button. If you hold it down It says:LCR Set OptionsExit: X Ver:5.5There is no X buttonSo restart it via the power switch and pretend I don't need to check that. Thanks for the optionsI see my set of shielded probes, that's nice. Maybe a little bit long for testing in low pF ranges but still pretty nice. The BNC jacks are labelled as follows -Lc Lp Hp HcLc = Loading capacitor? Inductive Capacitive? Left Channel? Low?Lp = Plate Load? Inductive Plate?Hc = Henries passive? Hot? .. You get it. What the heck do these mean?Hc = ?I plug the black clip leads into the left, and red into the right. With no attention to polarity or what is signal or ground and then put a 10K R between the clip leads. It works. I swap some leads on one probe. It works. I get a reading near 10K.. Okay that looks correctThen there's a whole range of other buttons. It seems like each button has a quick press function followed by a press and hold function.Okay so here's a description of each button. As far as I can tell, the auto function does a lot. But sometimes I'm not getting all the info I want like what the impedance of what a given coil is.. How do I view ESR? What is this 2.7Mohm thing? Okay the buttons descriptions -RNG / *image of gears* ( this button is blue )Zero / *recycle logo-ish image with 2 arrows going in a circle* ( this button is red )Hand / Aut ( this button is blue )CLR / *recycle logo-ish image with 3 arrows going in a circle* ( all buttons from here down are green )S *dot* P / ESRQTY / +/- %Freq / *picture of sine wave*What do all of these buttons do?

author: Yansi
author_rank: Super Contributor
timestamp: June 13, 2018, 10:19:07 pm
content: You should probably dig more into how these things work. The lead length does not matter (in theory of course) - thats why they are four of them! Two force ones (carrying current, that would be the two outer jacks noted as "c", and two voltage sense ones noted as "p". "c" might stand for current, not sure what "p" might be. L is just the Low voltage side where the I/V converter is and the H is the high side where the source is.Each probe has two BNCs. They are both connected to the same probe, making a kelvin point at the jaw. It does not matter, where each BNC goes, as far as one probe has connected both L jacks and the other probe both H jacks.Please do your homework a bit more thoroughly, before bitching about things the manufacturer is not responsible for.Can't say much about the user interface though.

author: Specmaster
author_rank: Super Contributor
timestamp: June 13, 2018, 10:41:26 pm
content: Yes, the manual could be a lot clearer, but I have one and have found it to be incredibly accurate, although I can't vouch for the inductance ranges though.

author: Yansi
author_rank: Super Contributor
timestamp: June 13, 2018, 10:54:33 pm
content: That is the sole purpose of a proper 4-wire impedance bridge - to be accurate means of impedance measurement.Even this cheap Chinese meter is miles ahead, of what a common two-wire measurement using your other (multi)meter can provide.Inductance measurement should be "accurate enough" too. Not sure where the limits are of this Chinese one are either.

author: buildafriend
author_rank: Newbie
timestamp: June 14, 2018, 12:09:59 am
content: Bitching? There's no bitching here manI'm just trying to learn this tool! Now at least I have some terms to look up. Thanks for the replies guys. Any more helpful information is invited.

author: WhichEnt2
author_rank: Regular Contributor
timestamp: June 14, 2018, 11:58:53 am
content: QuoteYep, some sort of low.Check the keysight impedance handbook:https://literature.cdn.keysight.com/litweb/pdf/5950-3000.pdf

author: buildafriend
author_rank: Newbie
timestamp: June 14, 2018, 01:36:47 pm
content: Thanks man will do.Has anyone tried altering the component values on the the 7.8K oscillator to put out 10kHz? I could try simulating this if there are no known values for the change..All the best,

author: Specmaster
author_rank: Super Contributor
timestamp: June 14, 2018, 01:44:44 pm
content: Can someone tell why this 10KHz or even higher is so important when it seems that from the manufacturers data sheets they test the ESR at 120Hz and the XJW01 has a frequency of 100Hz which is near enough?

author: WhichEnt2
author_rank: Regular Contributor
timestamp: June 14, 2018, 03:23:31 pm
content: They usually use 120 or 100 Hz for dissipation factor and 100 kHz for ESR.

author: Specmaster
author_rank: Super Contributor
timestamp: June 14, 2018, 03:48:58 pm
content: Quote from: WhichEnt2 on June 14, 2018, 03:23:31 pmJust looked Vishay data sheets and it clearly states ESR @ 120Hz, as have the other data sheets on Electrolytic caps.From mobile device so predictive text might have struck again

author: buildafriend
author_rank: Newbie
timestamp: June 14, 2018, 04:26:57 pm
content: from another forum -the leads that came with the XJW01 werent the greatest quality ,and they werent very flexible , what I found was that after you calibrate the leads and you dsconnect one ,you get a reading for the capacitance of that lead , if you do that in turn for each lead ,you start to see that there could be several pf's difference in each lead , this will scew the readings on the meter ,by a certain amount . When I made my new leads I used high quality cable ,very precisely measured ,in lenght ,and capacitance , in other words the more accurate your cables ,the more accurate the reading from the meter is . The original cables entered the probe clips on one side , which meant that one of the two cables to each probe was longer than the other ,that in turn means higher resistance and capacitance ,so calibration doesnt zero out the bridge so well.

author: AG7CK
author_rank: Regular Contributor
timestamp: June 15, 2018, 01:02:36 am
content: Impedance = Voltage / Current = Potential / Current(Force) Current High and Low : Hc, Lc(Sense) Potential High and Low : Hp, LpThe search "lcr lp lc hc hp" gives (on my pc, i.e. - ymmv) first link being:http://hiokiusa.com/wp-content/uploads/pdf/28261-LCRappguide-2016.pdf. On page 5 of 28 I find the below attached figure.The excellent but excentric XJW01 is imo only for people whoalreadyknow how to use a generic LCR meteralready(yep, yhat is a double).People w/o willingness and ability to search and learn on their own can imo use it to "indicate" some value or another for ohm, farad and henry - but little else.Hence go find and study 3-10 user manuals for LCR meters from Japan, Germany and USA, and you will see that many questions in this thread evaporates into thin air.

author: WhichEnt2
author_rank: Regular Contributor
timestamp: June 15, 2018, 10:13:09 am
content: Quote from: Specmaster on June 14, 2018, 03:48:58 pmI checked it just now on random vishay cap series, as you.http://www.vishay.com/docs/28420/160rla.pdf

author: AG7CK
author_rank: Regular Contributor
timestamp: June 15, 2018, 10:52:13 am
content: Well, 2x50Hz is 100Hz and 2x60Hz is 120Hz, so it all depends on the grid line frequency of the country in which the datasheet was written or which it was written for.But it doesn't mean anything at all. Start read some manuals, and you will soon know it all.

author: Specmaster
author_rank: Super Contributor
timestamp: June 15, 2018, 11:11:13 am
content: And which manuals would they be?

author: AG7CK
author_rank: Regular Contributor
timestamp: June 15, 2018, 11:38:53 am
content: Quote from: Specmaster on June 15, 2018, 11:11:13 amThank you for asking. I will compile a list of imo useful and easy to read manuals below. In the mean time:1) Please search the web for "lcr 100hz 120hz". You will find snippets like:- 100Hz and 120 Hz test frequencies are generally used in capacitance measurement of electrolytic capacitors which are used as power line voltage rectifiers.- UK— 50 Hz - Ripple frequency = 100 Hz- to filter power line frequency effects (50/100Hz or 60/120Hz)- Test frequencies: 100Hz, 120Hz, 1kHz and 10kHz.This will set you off finding info yourself.2) Read the very good manual for DE-5000 (a very good cheap all-round instrument). There are different versions, but this was the first I found:https://www.ietlabs.com/pdf/Manuals/DE_5000_im.pdfIf you search "100 Hz" in the pdf-file manual, you will find the string "100 Hz / 120 Hz / 1 kHz / 10 kHz / 100 kHz" on page 46 of 52.3) Now go search "100 Hz / 120 Hz / 1 kHz / 10 kHz / 100 kHz" on the web, and you will get "a ton" of user manuals for LCR meters.Voila, I don't have to compile a list after all ... (joking, I will put up a list later).Good luck searching and reading.

author: buildafriend
author_rank: Newbie
timestamp: June 15, 2018, 11:41:18 am
content: Quote from: AG7CK on June 15, 2018, 01:02:36 amThe recently recommended paper on impedance measurement was extremely helpful, now you've got me digging. And yeah I wish I could afford a normal LCR meter before this one! There's no reason to settle for a lesser meter when you have the ability to learn a better one that costs less. Does this not count as researchThe old art of communicating with peopleThis adds clarity, thank you!!

author: WhichEnt2
author_rank: Regular Contributor
timestamp: June 15, 2018, 11:44:44 am
content: QuoteReally? And why do you insidiously ignore 100 kHz in such complex math equations?

author: AG7CK
author_rank: Regular Contributor
timestamp: June 15, 2018, 12:04:57 pm
content: Quote from: WhichEnt2 on June 15, 2018, 11:44:44 amI like your sense of humor. Pass me the popcorn, please.I must admit that I cannot count to 100.000But there are historical reasons for the universally accepted test frequencies of (all in Hz):- 100/120 (explained over)- 1k, 10k (standard caps and more - intermediate values)- 100k (RF stuff)But this is also searchable for those who bother to do it. So no need for me to write a half baked explanation of things that are already out there.PS If you search the web for "eevblog xjw01 7.8khz" you will know the reason why this meter does not conform to 10kHz. And if you search the web for "lcr meter 9.6khz" you will learn even more.Happy searching.

author: Specmaster
author_rank: Super Contributor
timestamp: June 15, 2018, 12:17:13 pm
content: Quote from: AG7CK on June 15, 2018, 12:04:57 pmSo in the case of someone like me who is not really RF but more into audio and power supply smoothing and filtering the 100Hz and 120Hz testing frequency is surely just fine?I have just read the manual for DE5000 and yes, while it does support 1KHz, 10KHz 100KHz, 100Hz and 120Hz, the default is 1KHz but it does not explain why it defaults to IHz test frequency and likewise it fails to mention why does it support other frequencies as well?

author: WhichEnt2
author_rank: Regular Contributor
timestamp: June 15, 2018, 01:53:39 pm
content: QuoteSure.QuoteThis and other (decision not to use ICL7135) nuances of xjw01 design is clearly described in machine-translated doc for early revision of meter.QuoteResults is fully stuffed with some lcr meter which is made by Chroma. I learned that their manual for that meter and appnotes on lcr related info not nearly as good as same docs from HP / Keysight.Very unexpectedly.I'd bet you meant something about difficulties in implementation precise 10 k vs using just-close-enoguh don't-even-have-to-use-extrapolation 9.6 k.

author: AG7CK
author_rank: Regular Contributor
timestamp: June 15, 2018, 08:36:34 pm
content: Well, I guess I should have kept my hands out of this hole of worms ...When in my naivety I search "lcr meter why 9.6khz not 10khz" or similar, I get answers like '10 kHz = 9.6 kHz' even from an Agilent dokument:Code:Agilent U1731B/U1732B Dual Display Handheld LCR Meter - Keysightliterature.cdn.keysight.com/litweb/pdf/U1731-90059.pdfrequirement. This affixed product label indicates that you must not .... The 20,000-count dual displayhandheld LCR meters (U1731B and ...... 10 kHz = 9.6 kHz.878A and 879 Dual Display LCR Meter - Mouser Electronicshttps://www.mouser.com/ds/2/43/879_manual-707041.pdfcontrolled meter for measuring functions of inductance, capacitance and ... Extremely simple to operate,the instrument not only takes ..... 10KHz= 9.6 KHz.Tenma 72-1025 LCR Meter - UNC Physicshttps://users.physics.unc.edu/~sean/Phys351/techresource/docs/Tenma72-1025.pdfBenchtop LCR Meter. Model 72-1025 ...... mode. The dark areas are not provided on this meter.100Hz. 120Hz. 1KHz. 10KHz. Resistance .... 10KHz= 9.6 KHz........WTF ...The reason why 10 kHz = 9.6 kHz and 7.8 kHz is close enough to 10 kHz, is probably related to microprocessor crystal frequencies and prescaler / divider factors (used for test oscillators).So 100/120 - 10k/9.6k or 7.8k really doesn't matter. Start by choosing low frequency 100 (or 120) for PSU electrolytes, 1k/10k for micro- to nanofarad sized audio stuff and similar, and 100k for handfuls of picofarads.The manualhttps://users.physics.unc.edu/~sean/Phys351/techresource/docs/Tenma72-1025.pdfover is good. Read it and go search on your own.---ooo---Edit:Copy fromhttp://literature.cdn.keysight.com/litweb/pdf/U1731-90059.pdf:"Test frequency accuracy:±0.1%...100 Hz = 100 Hz120 Hz = 120 Hz1 kHz = 1010 Hz10 kHz = 9.6 kHz..."

author: nctnico
author_rank: Super Contributor
timestamp: June 15, 2018, 10:34:56 pm
content: Quote from: buildafriend on June 15, 2018, 11:41:18 amDefine normal LCR meter. After I bought the XJW01 I also bought an old HP LCR meter (something with ...74) which supported 100kHz as well. It turned out the XJW01 is way more accurate especially for low values (like the milli-ohm range). Ofcourse no bias voltage but with a simple external circuit (DC blocking capacitor) you can add that to the XJW01 as well. End of story: the HP LCR has left the building.I got a network analyser instead which can do frequency sweeps as well.

author: Specmaster
author_rank: Super Contributor
timestamp: June 15, 2018, 10:57:16 pm
content: Quote from: nctnico on June 15, 2018, 10:34:56 pmYes I believe that the XJW01 is pretty accurate and of course it has another big advantage over the HP LCR meter, size, the HP one is massive, its as big as a 1740A scope.

author: The Electrician
author_rank: Frequent Contributor
timestamp: June 16, 2018, 01:56:09 am
content: Quote from: Specmaster on June 15, 2018, 11:11:13 amThis one is good:http://www.componentsengineering.com/wp-content/uploads/pdfs/LCR-Measurement-Primer.pdf

author: Specmaster
author_rank: Super Contributor
timestamp: June 16, 2018, 09:37:53 am
content: Quote from: The Electrician on June 16, 2018, 01:56:09 amYes thats a good one, but let me spin it on its head now, all of the ESR charts on capacitors that I've seen have all been on electrolytics and are taken at 100Hz or 120Hz. In fact on some LCR/ESR testers even have a table of expected results printed on them, and once again they are for electrolytics at the same frequencies.Are tables for there tables that show what a good ESR reading should be at 100KHz and also at 10KHz for these other caps?It has always been the case in my experience that these other caps like ceramics etc have 2 failure modes open or shorted circuited. The capacitance may drift a bit over time and this can checked on the testers but nowhere have I ever come across any form of a table or even a mention about the passable ESR values for these, nor have I heard anyone mention that this is a problem until this thread. So is this a consequence of the ever increasing frequencies being used today or what?

author: The Electrician
author_rank: Frequent Contributor
timestamp: June 16, 2018, 09:10:27 pm
content: Quote from: Specmaster on June 16, 2018, 09:37:53 amA long time ago in the first half of the 20th century, before computers, measuring capacitors was done with manual bridges; things that looked like this:https://www.bing.com/images/search?q=impedance+bridge&qpvt=impedance+bridge&FORM=IGREAt that time 1 kHz was more or less a default frequency for measurement of caps.After the second world war, there was a rapid increase in electronic technology and electrolytic capacitors became the standard item for ripple filtering in power supplies. Since electrolytic caps were usually polarized, it was necessary to avoid applying a reverse voltage to them, but to measure them it was necessary to apply an AC voltage, and AC voltage goes negative for half the cycle; what to do? As it happens, electrolytic caps don't mind a very small reverse voltage for a short time so the manufacturers got together and established a standard. The standard was to apply an AC frequency similar to what the cap would see in use. This would be double the grid frequency most of the time because of the common full wave rectifier circuits. So the standard, still in use today, is to measure at 120 Hz (twice the 60 Hz grid frequency; 100 Hz in Europe, close enough) with an applied voltage of 1/2 volt RMS.Since in the 1940's and 1950's when the standard was established, switching power supplies operating at frequencies above 20 kHz were almost non-existent, there was no need to know or measure ESR at those frequencies. But, nowadays switchers are ubiquitous, and manufacturers of electrolytics intended for use in switchers specify impedance at 100 kHz. The impedance and ESR of typical electrolytics have the same numerical value at 100 kHz, so measuring impedance is the same as measuring ESR. This fact allows a low cost instrument to measure ESR; see the long thread I reference below for details about this. The 100 kHz frequency is sort of in the middle range of commonly used switcher operating frequencies although megahertz switchers are looming.So these are the reasons for 100 Hz, 120 Hz, 1 kHz and 100 kHz measurement frequencies. But what about 10 kHz? When the first low cost LCR meters were being designed, 100 kHz was enough harder to do than 10 kHz that 10 kHz was what you got. It was still useful to get a better idea of capacitor parameters at switcher frequencies than just 1 kHz. And a user might have another reason to measure at or near 10 kHz, and it's easy to include it in modern instruments.Finally, LCR meters 20 years ago were still somewhat expensive and repair techs couldn't afford one. But then someone noticed that at 100 kHz a typical electrolytic with capacitance of, say, 100 uF or more has a reactance much less than 1 ohm; .016 ohms for 100 uF and less for larger sizes. Because the reactance is so low, it's common that the ESR will be greater than the reactance and so the reactance can be ignored when measuring the ESR. At lower frequencies where the reactance is larger than the ESR, a phase sensitive detector must be used to measure ESR, and this increases the cost of the meter. A method of using digital pulse techniques to measure ESR resulted in ESR meters costing much less than the typical LCR meter of the time. One of the first was the "Blue ESR meter":https://anatekinstruments.com/products/fully-assembled-anatek-blue-esr-meter-besrMany meters using this technique have been developed since then, and they are mainly useful to repair technicians (and hobbyists) to locate defective electrolytics. Since the concept of ESR was not very useful to a repair tech when the only available meters cost many thousands of dollars, those techs were not familiar with what a good cap's ESR would be. The availability of ESR meters that a repair tech could afford meant that somehow techs would have to know what good and bad ESR would be for various electrolytics. Hence, tables of typical good ESR appeared:https://www.eevblog.com/forum/beginners/esr-values-for-electrolytic-caps/People complain about these tables, rightly so, and in truth there is great variablilty in electrolytic capacitor ESR and the tables are really just useful as rough guidelines, which is better than nothing. The best thing to do is measure the ESR of a known good sample of the electrolytic in question.The price and capability of integrated circuits has continued to improve over the years, and now there are fully capable LCR meters available for about the same price as the pulse technique ESR meters, for example the DE5000.I explain in detail about capacitor ESR here:https://www.eevblog.com/forum/projects/impedance-lcr-esr-meters/msg459303/#msg459303Also have a look at this thread:https://www.eevblog.com/forum/projects/capacitor-measurements-on-an-impedance-analyzer/msg178362/#msg178362

author: Specmaster
author_rank: Super Contributor
timestamp: June 16, 2018, 10:52:07 pm
content: Thank you thats very informative but that still doesn't solve the problem definitively because if I have correctly understood it, to effectively test a capacitor, you need to know what type of circuit it is being used. Take the case of power supply, there are many questions that need to answered before you can be certain if the capacitor under test is suitable not just at the time of being tested but also was it suitable for the application at the time of the PSU being designed and built?You talk about switchers coming that will operate not in 10s or 100s of KHz but in MHz which is going to cloud the issue even further, do we even have capacitors that would be suitable for such switchers?However, my main point still remains unanswered, speaking purely as a person who is primarily interested and involved in repairing items as opposed to designing and developing some new piece of equipment that is designed at high frequencies and maybe even running into the GHz regions. That would mean dealing with more mundane frequencies from 100Hz to 100Khz for switchers. Where are the tables that show the acceptable ESR values for capacitors used in such instances in the discussion you refer tohttps://www.eevblog.com/forum/beginners/esr-values-for-electrolytic-caps/there are many tables (sources are not quoted or the frequncies tested at), some of these tables are actually printed on the various test instruments, ie, the Blue meter and the BK tester. There is in that thread much debate and disagreement on how to test and what is and what isn't acceptable, so how are repair engineers/technicians like myself supposed to get it right?The industry really needs a table that is fit for purpose and also proper testers that don't cost an arm and a leg or need massive amount of bench/shelf space that can test these capacitors correctly for the average consumer type of products, this must be a doable thing surely?So what advice would you give in that instance and what tester would meet that requirement and why? If I read you correctly, you seem to advocate the DE-5000 but I have read the manual for that and it is very hard to understand and it doesn't even mention what frequency to test capacitors at, it just mentions what frequencies it is capable of providing which is useless in reality to most people, especially given that capacitor failure is one of the biggest if not the biggest cause of modern equipment failing.

author: nctnico
author_rank: Super Contributor
timestamp: June 16, 2018, 11:12:44 pm
content: When it comes to electrolytic capacitors then 100kHz is more than enough. If you want to make certain a capacitor from a (failed) circuit still meets it's specs you'll need to read it's datasheet and measure to see if it meets the specs or not.For much higher frequencies you'll see Tantalum and MLCC capacitors. These fail open or short so any DMM with capacitance measurement ability is suitable to check these for value (unless ofcourse the value falls outside the measurement range).

author: Specmaster
author_rank: Super Contributor
timestamp: June 16, 2018, 11:53:46 pm
content: Quote from: nctnico on June 16, 2018, 11:12:44 pmI don't use DMM's with capacitance range, they are always miles out, these are what I currently use and the highest known frequency is 7.8KHz on the XJW01, the frequency of the other 2 is not known.

author: nctnico
author_rank: Super Contributor
timestamp: June 17, 2018, 12:06:08 am
content: The VC8145 DMMs I have are spot on down to the nf range using long wires.

author: Specmaster
author_rank: Super Contributor
timestamp: June 17, 2018, 12:33:15 am
content: As far as I know, mine are also pretty much spot when it comes to measuring the capacitance, but what's more important to me is the ESR values.

author: SteveSi
author_rank: Contributor
timestamp: October 15, 2019, 04:17:45 pm
content: Video here on how to use and what buttons do and what screen means, etc.https://youtu.be/NgSRAg9lLYg#

author: scopeman
author_rank: Frequent Contributor
timestamp: December 28, 2020, 04:22:53 pm
content: Hello,I know that this thread is a bit old but I wanted to chime in and give you an opinion on the XJW01.I own several LCR bridges and meters. I have the following GR units: 1650A, 1650B, 1656. I had a 1657 DigiBridge but sold it before I owned the XJW01. I have a couple of HP4260A's that I have restored and A HP4262A with the comparator option that has recently been calibrated as well as a Wayne-Kerr 4250 which is dead on and has become my favorite DigiBridge. The 4250 does 120Hz, 1KHz, 10KHz and 100KHz. The W-K is the one I use when I want the best precision and the only bench unit that has 100KHz.I bought the XJW01 as it was very inexpensive and interesting and small. Once I got it I tore it apart and found much to my surprise that it was very well built and the soldering and parts placement was as good as any PCB assemblies I have seen as I have spent the last 40 years designing electronics for a living.So I put the unit back together and proceeded to compare it against my W-K 4250 using the calibration resistors supplied with the XJW01. Attached is a spreadsheet that shows the results of that test.I did also do some comparisons on various inductors and capacitors and found similar agreement between the two devices, although I did not take the time to record this I found that for all practical purposes the performance within the same selection of frequency ranges was virtually identical. I found that the indication at 7.8KHz to be virtually the same as the indication at 10KHz on my W-K. I do wish that it had 100KHz but the lack of that range does not take away from the performance or utility of the device. Maybe when I have the chance and the time I will add the capacitor and inductor test results to the spread sheet.In short the XJW01 is a very good buy for the money. The only thing I would like to do is to find a source for the empty case that the XJW01 is built in to build a battery pack that would fit on the rear of the case. So far I have not been able to find one. If anyone knows of a source please let me know.One further comment there is a fellow on the internet that has an instructional video on the XJW01 and he offers an English manual for 3 USD. I highly recommend that you purchase that as it explains in detail the button functions and goes through the calibration procedure (I did not alter the as received calibration in any of my testing but it is good to know that I have the correct procedure to do this if I needed to do so).There are also extensive Chinese archives one can find on the web on the various designs of this LCR meter including code and PCB layouts but I have not been able to find this information on the latest version. If anyone finds it I would like to have this information.All in all the XJW01 is one of the best Chinese products I have come across, definitely worth the cost of less than a meal for 6 at McDonalds!SamW3OHM

author: Specmaster
author_rank: Super Contributor
timestamp: December 28, 2020, 05:05:47 pm
content: Which model of the XJW01 do you have, is the one as shown in my photo further up the page or is it the silver one that has a flat format? I'm glad that you seem to concur with me that it is a very worthwhile piece of kit yet so many here seem to dismiss it entirely out of hand, instead favouring the XE5000 which costs loads more but does have the higher test frequency. For my intended purposes, the frequencies it has are more than adequate as I'm more interested in the testing of electrolytics and tants on power rails as in my experience these are the ones that cause the most problems and those are not used at higher frequencies, which is where ceramics etc take over and as such are relatively inexpensive to actually substitute to see performance increases as a result.

author: nctnico
author_rank: Super Contributor
timestamp: December 28, 2020, 05:48:36 pm
content: Quote from: Specmaster on December 28, 2020, 05:05:47 pmI agree. I still have & use the XJW01 from the first post of this thread.

author: Specmaster
author_rank: Super Contributor
timestamp: December 28, 2020, 05:58:58 pm
content: Quote from: nctnico on December 28, 2020, 05:48:36 pmThat’s the same one I have. I don’t for sure but I suspect that a lot of people may reject it out of hand because it has that hand made look about the case, in particular with area around the screen which is the result of trying to use a standard case instead of developing a dedicated one. The new version gets round that issue but I think it’s form factor then becomes an issue to many, whereas the DE5000 looks like a multimeter and as a result is more acceptable aesthetically.

author: indman
author_rank: Super Contributor
timestamp: December 28, 2020, 06:41:50 pm
content: I made a fiberglass case for my device with my own hands, I took the stand from an old multimeter. I really didn't like the color of the original buttons - the bright color hurts the eyes, so I picked up a calm gray palette. I also have a DE-5000, but I like the XJW01 more for ease of use and for displaying the results..

author: Specmaster
author_rank: Super Contributor
timestamp: December 28, 2020, 06:57:59 pm
content: Quote from: indman on December 28, 2020, 06:41:50 pmThat looks rather good, well done. I think it would be better if they had also included the push-in terminals like the DE-5000 so you didn't need to have those leads laying across the bench.

author: ResistorRob
author_rank: Regular Contributor
timestamp: December 28, 2020, 06:59:12 pm
content: I was looking at picking up the Hantek LCR meter. Both have 0.3% accuracy. The Hantek has a lot of frequency ranges up to 100K, so is there any advantage to buying this instead? To be honest I don't need anything super accurate, because I will just be testing old stock to make sure they are good before using them and to check caps in old equipment. My budget is up to $200, but prefer to keep under 150 if possible, so open to all LCR meters suggestions.

author: indman
author_rank: Super Contributor
timestamp: December 28, 2020, 07:07:05 pm
content: Quote from: Specmaster on December 28, 2020, 06:57:59 pmThank you, I agree with you. I would also like to note the very low quality of Chinese BNC connectors. Once I got this kit, my first desire was to get rid of these substandard BNCs and replace them with Canare BNCs.Quote from: ResistorRob on December 28, 2020, 06:59:12 pmThis meter has not very good reviews from the owners. A raw product, I do not recommend it for purchase.If 100 kHz is important for you for measurements, then I advise you to pay attention to the time-tested DE-5000 or the new device from UNI-T UT622C

author: floobydust
author_rank: Super Contributor
timestamp: December 28, 2020, 08:19:10 pm
content: I bought an XJW01 last year "PCB Rev. 1.1", "Circuit Rev. 3.1", "Date: 2017/03/28" the price is reasonable.Calibration instructions took a while to translate, a lot of pain and actually the hardest aspect of the kit.They come with a cheap op-amp U108 is either TL081 or NE5532. The meter does OK, not great, I cannot read relay coil inductance or low value WW resistors (inductance) for some reason. It's as if the noise floor is poor. It struggles at 7.8kHz too, the MCU is slow.There are several enhancements to F/W and H/W that the West does not get. They went STM32 and AD9850 DDS but the designer got tired of his work being ripped off so I think he closed off the design. The Russian's competed with their "RLC Meter Digital" design, all using HP's original design.

author: ResistorRob
author_rank: Regular Contributor
timestamp: December 29, 2020, 02:03:38 pm
content: Quote from: indman on December 28, 2020, 07:07:05 pmI watched a couple reviews on Youtube covering the Hantek and they gave it really high marks. I looked into pretty heavy before, but don't recall what the pros and cons were. Thanks for the heads up on the UNI-T. Somehow I missed that one. Seems new and almost no mention of it online. Checks all the boxes of what I'm looking for. That's definitely the one I'm going for. They charge a lot more for the "e" model which adds DSR, so will probably just order the "c" version.

author: precaud
author_rank: Frequent Contributor
timestamp: December 29, 2020, 03:04:17 pm
content: There appears to be a new version of the XJW01, though it's not labeled as such, it is branded "Rod rain". Black case, 2-layer pcb with SMD components, built-in battery charger, and the BNC's are along the front edge.https://www.ebay.com/itm/Digital-LCR-Bridge-Tester-Resistance-Inductance-Capacitance-Meter-ESR-w-Battery/284098649802

author: indman
author_rank: Super Contributor
timestamp: December 29, 2020, 06:05:14 pm
content: Quote from: precaud on December 29, 2020, 03:04:17 pmNo, I don't like this model. A 2-line display(or small text on LED) instead of a 4-line display significantly impairs the usability of the device. In addition, the location of the BNC connectors assumes that the device will be in a horizontal position and a person will have to look into the display from above. It also complicates a comfortable measurement environment.

author: exe
author_rank: Unknown
timestamp: December 29, 2020, 08:07:46 pm
content: Quote from: precaud on December 29, 2020, 03:04:17 pmIt goes only to 7.8KHZ

author: precaud
author_rank: Frequent Contributor
timestamp: December 30, 2020, 02:49:34 am
content: Quote from: exe on December 29, 2020, 08:07:46 pmIt's the same for them all!Quote from: indman on December 29, 2020, 06:05:14 pmAgreed on the display lines, but I like the BNC position, you can easily attach fixtures to it. And having batteries inside with charger is a plus.My post is not to condone, only to inform...

author: pizzigri
author_rank: Regular Contributor
timestamp: October 09, 2021, 12:20:21 pm
content: Quote from: floobydust on December 28, 2020, 08:19:10 pmHello Floobydust,For some coincidence I have two of these meters, one I got as a gamble on Amazon as it was listed for something totally different for like 20 US dollars.... well in any case, i wanted to ask you if you think the device could be improved, both by changing the admittedly poor bnc connectors and maybe replace the op amp you mention above with a better part (which one?).Also, I plan to change the Kelvin clips with something better- would the GWinstek type clips be an improvement to the performance of the LCR meter? I would have to modify them to use BNC rather that Banana clips though.Best,FrancoEta mod the name I mistook a fellow member for another...

author: parasole
author_rank: Contributor
timestamp: February 28, 2023, 07:27:23 am
content: Quite an old topic, but let me answer you, who knows, maybe you still need itSince I killed my DE5000, I was in an intense investigation for a DYI meter, not because it would be cheaper, but because I want full control and independence from a vendor who told me the repair will be more than a new meter...Now thanks to this forum I think I found most of the available DIY meters, and this one seems to be simplest in the way it is executed, although all of them are more or less equal and use the same bridge architecture, just for this one I have everything in my hands including source code.Possible improvements I see here are not that many, considering it is an entry-level unit, changing to a much better OPA has no reason, I am intending to use LF347 simple since I have many of them and they are a little bit improved version of TL082/84. Basically, for the front end, you need a high impedance input (FET input) and low voltage offset, so keeping stock TL082/84 or a little bit better OPA is OK. This meter has 7k8 highest test frequency hence even for G=9 as one stage is having, there is no problem with bandwidth. However, one point to look for is current sense ref resistors, having those at list 0.1% tolerance and low TCR (planning for 25ppm in my case) would help to increase the stability and calibration. One possible source of noise tests sine signal generation, maybe it would benefit from a better filter, but that requires more verification if that indeed is the case.

author: mawyatt
author_rank: Super Contributor
timestamp: February 28, 2023, 03:28:37 pm
content: How did you destroy your DE-5000?Did you attempt a repair, or was it a total loss?Best,

author: exe
author_rank: Unknown
timestamp: February 28, 2023, 03:47:28 pm
content: Quote from: mawyatt on February 28, 2023, 03:28:37 pmMy guess is by connecting a charged capacitor.

author: precaud
author_rank: Frequent Contributor
timestamp: February 28, 2023, 03:58:36 pm
content: FWIW, a couple weeks ago I borked my XJW01 by accidentally connecting a charged 'lytic. Fortunately, the input protection diodes did their job admirably. Replaced a couple shorted 1N4148's (easily accessible) and it was back in business.As for the stability, at first I thought it may be a problem, but quickly realized that my expectations and use habits were the the issue. When I use my HP meters, I always give them time to warm up. But with the XJW01 (and other handheld meters) I tend to use them immediately after power-up, unrealistically expecting them to be fully accurate and stable. Fact is, it should be no surprise that there is significant drift (esp when measuring low impedances) until it has reached stable temps inside.

author: mawyatt
author_rank: Super Contributor
timestamp: February 28, 2023, 05:31:28 pm
content: Agree, warmup is always required for accurate results, whatever the instrument is. However, the DE-5000 seems good right from Power On, even with the previous Open/Short Cal values, assuming of course that the same measurement adapter is utilized.Think that most of the performance for the DE-5000 is attributed to the Cyrustek Chip set utilized, seems like a sophisticated mixed-signal chip set, altho this link doesn't show much about what's inside!!http://www.cyrustek.com.tw/wp-content/uploads/ES51920.pdfBest,

author: coromonadalix
author_rank: Super Contributor
timestamp: February 28, 2023, 05:37:13 pm
content: if you respect the DE-5000 open and close calibrations, never had bad surprises with it

author: parasole
author_rank: Contributor
timestamp: March 01, 2023, 12:56:05 am
content: Quote from: exe on February 28, 2023, 03:47:28 pmYou guess it rightStupid mistake after almost 10 years of use...Quote from: mawyatt on February 28, 2023, 03:28:37 pmYes, wrote to both, Cyrustek and DER, first ignored my mail, and the second requested to send it for repair in exchange for 70USD plus postage... new one for me (as I am now in Japan) is about 90, so not a big deal to get one...DIY, in fact, will be probable twice more expensive as I plan to build at least two or even more variants and compare them... The turning point was DER answer, I don't like the lack of control over the unit and no chance for repair by replacing the analog front-end chip, digital is still ok.Embarked now on a DIY version and have a lot of fun learning about digital bridges and the math behind themQuote from: mawyatt on February 28, 2023, 05:31:28 pmAfter inspecting DE5000 front-end PCB circuitry, I am sure that the front-end chip is nothing more than a bunch of analog switches and OPA as you may find in any digital bridges out there, even I-sense ref resistors have the same values. The second chip is handling the display and all the math, again the same as any other DYI, one like Elector is more sophisticated while xjw01 or LCR2 Go is probably on the lower side.Another aspect is they seem to have factory calibration as there is a serial memory chip installed, and that is a pro point for DE5000.Quote from: precaud on February 28, 2023, 03:58:36 pmExactly, and unfortunately, DE5000 luck any even this rudimentary type of protection...Quote from: coromonadalix on February 28, 2023, 05:37:13 pmI fully agree, it was a great meter, bad enough I destroyed it by stupid accident... On another side, if that would not happen, I would never learn about these devices' inner work

author: parasole
author_rank: Contributor
timestamp: March 20, 2023, 01:03:55 pm
content: Quote from: dannyf on June 04, 2016, 01:36:14 pmHinot sure Danny will read this post so questioning the publicRegarding AFE, what would be the major benefit of using a dedicated diff-amp for V and I? To me, it looks like sharing a single diff-amp for both channels would be better as the same offset/bias will be applied... do I miss something?

author: sonpul
author_rank: Regular Contributor
timestamp: March 20, 2023, 06:13:56 pm
content: Quote from: parasole on March 01, 2023, 12:56:05 amMaybe it will helphttps://www.ittsb.eu/forum/index.php?topic=714.0

author: parasole
author_rank: Contributor
timestamp: March 20, 2023, 11:54:26 pm
content: Quote from: sonpul on March 20, 2023, 06:13:56 pmThanks, but in my case the stored energy was too high as AFE chip got fully shorted. I desoldered it and the meter may start, but then complain of an error and shutdown. I think the chipset datasheet is confidential for a reason, I am pretty confident by now that AFE side consists of a number of analog switches and diff PGA and probably would not be that difficult to substitute should we have a good chipset description...

author: CharlotteSwiss
author_rank: Frequent Contributor
timestamp: August 17, 2024, 01:16:24 pm
content: The kind user Indman recommended this device to me. I already have a T4, but I would like to have a device that also reads the values ​​on the circuit, so this could be for me. Is it sold in different kits? I would like to have all the options available. I searched, but found very different prices. Any help? Thanks

author: indman
author_rank: Super Contributor
timestamp: August 17, 2024, 02:37:56 pm
content: CharlotteSwiss, I'm not sure if this link will work for you, but try ithttps://aliexpress.com/popular/xjw01.html

author: CharlotteSwiss
author_rank: Frequent Contributor
timestamp: August 17, 2024, 05:09:42 pm
content: Quote from: indman on August 17, 2024, 02:37:56 pmThanks indman. I explained myself badly, I don't want the link, I just wanted to be sure that the device was the right one. But above all I would like to understand which 'kit' to get. Since I'm ordering, I would like to have all the measuring cables.Would the complete kit be the one in my image? Device; support; power supply; two measuring cables (I don't understand the difference). Thanks

author: indman
author_rank: Super Contributor
timestamp: August 17, 2024, 05:17:12 pm
content: Quote from: CharlotteSwiss on August 17, 2024, 05:09:42 pmYes, it's a complete set! Have a good purchase, be sure to make a video of unpacking the product and check its serviceability.

author: CharlotteSwiss
author_rank: Frequent Contributor
timestamp: August 17, 2024, 06:59:29 pm
content: I have never taken these precautions, I have generally never had any bad surprises. Maybe there are clones of this device?

author: floobydust
author_rank: Super Contributor
timestamp: August 18, 2024, 05:42:54 am
content: No, they are all pretty much the same. A few are old through-hole boards.It has eight MELF clamp diodes for protection, easy to replace if needed.

author: pizzigri
author_rank: Regular Contributor
timestamp: September 23, 2024, 09:23:32 am
content: Long time no see, but I am back! I just read the thread and i am curious as to which resistors to replace with better ones. Anyone can point them out to me?I found the highly counter-intuitive and convoluted calibration procedure in one of the pdf manuals for this meter, and although i also have a DE5000 I still like this one. I does agree (both XJW01 i have) with the DE5000 too, which is not bad.Also, I have FW 3.0 (Putian 2012), are there any updates to it?Franco

author: pizzigri
author_rank: Regular Contributor
timestamp: September 23, 2024, 09:42:25 am
content: Sorry, the FW revision I have is 5.5 - the 3.0 is the hardware revision.