Author Topic: XJW01 Auto LCR meter review ($120 bench top LCR meter)  (Read 42708 times)

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Offline nctnico

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XJW01 Auto LCR meter review ($120 bench top LCR meter)
« on: March 20, 2014, 08:46:34 pm »
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...

Specs
R    0.0002 Ohm — 9.999 MOhm
C    0.1 pF — 10000uF or more
L    0.01 microH — 1000 H
D,Q    0.001 — 9999

For 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 impression
After 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  :palm: .  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.

Overall
When 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:


« Last Edit: March 20, 2014, 08:51:26 pm by nctnico »
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Offline Carrington

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Re: XJW01 Auto LCR meter review ($120 bench top LCR meter)
« Reply #1 on: March 20, 2014, 09:04:55 pm »
Interesting!
But no more specification? Basic accuracy, for example.

Edit:
Ok, 0.3%.
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http://easy-taobao.com/taobao/view/id/22601240432



Within a "economic" range, I like these two: AT825 and U822C.
« Last Edit: March 20, 2014, 09:25:50 pm by Carrington »
My English can be pretty bad, so suggestions are welcome. ;)
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Offline nctnico

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Re: XJW01 Auto LCR meter review ($120 bench top LCR meter)
« Reply #2 on: March 20, 2014, 10:54:22 pm »
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.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline quantumvolt

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Re: XJW01 Auto LCR meter review ($120 bench top LCR meter)
« Reply #3 on: April 21, 2014, 03:59:44 am »
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 in http://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 ...



« Last Edit: April 21, 2014, 04:15:25 am by quantumvolt »
 

Offline Vgkid

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Re: XJW01 Auto LCR meter review ($120 bench top LCR meter)
« Reply #4 on: April 21, 2014, 04:19:06 am »
I'm curious why they chose the 7.8khz frequency, It is not to far off from the usual 10K frequency.
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Offline echen1024

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Re: XJW01 Auto LCR meter review ($120 bench top LCR meter)
« Reply #5 on: April 21, 2014, 04:27:41 am »
I can translate the schematic if needed... my Chinese isn't too rusty I hope.
I'm not saying we should kill all stupid people. I'm just saying that we should remove all product safety labels and let natural selection do its work.

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Offline SeanB

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Re: XJW01 Auto LCR meter review ($120 bench top LCR meter)
« Reply #6 on: April 21, 2014, 04:59:16 am »
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.
 

Offline Vgkid

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Re: XJW01 Auto LCR meter review ($120 bench top LCR meter)
« Reply #7 on: April 21, 2014, 06:19:58 am »
Thanks, I figured that they could use the micro to generate a range of frequencies.
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Online BravoV

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Re: XJW01 Auto LCR meter review ($120 bench top LCR meter)
« Reply #8 on: April 21, 2014, 07:06:29 am »
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.  :-//

Offline dannyf

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Re: XJW01 Auto LCR meter review ($120 bench top LCR meter)
« Reply #9 on: April 21, 2014, 10:33:42 am »
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.
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Offline Carrington

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« Last Edit: April 21, 2014, 07:23:35 pm by Carrington »
My English can be pretty bad, so suggestions are welcome. ;)
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Offline quantumvolt

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Re: XJW01 Auto LCR meter review ($120 bench top LCR meter)
« Reply #11 on: April 21, 2014, 06:12:56 pm »
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 PCB  :o

Unless 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.
 

Offline Carrington

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Re: XJW01 Auto LCR meter review ($120 bench top LCR meter)
« Reply #12 on: April 21, 2014, 06:28:41 pm »
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 PCB  :o

Unless 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.
It 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
« Last Edit: April 21, 2014, 06:35:17 pm by Carrington »
My English can be pretty bad, so suggestions are welcome. ;)
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Offline quantumvolt

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Re: XJW01 Auto LCR meter review ($120 bench top LCR meter)
« Reply #13 on: April 21, 2014, 06:37:21 pm »
Thanks.
 

Offline Hydrawerk

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Re: XJW01 Auto LCR meter review ($120 bench top LCR meter)
« Reply #14 on: April 21, 2014, 07:49:01 pm »
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-p722-483
https://www.eevblog.com/forum/testgear/cheap-lcr-meter-cem-dt-9935/
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Offline Carrington

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Offline Hydrawerk

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Re: XJW01 Auto LCR meter review ($120 bench top LCR meter)
« Reply #16 on: April 21, 2014, 09:17:38 pm »
It runs on a 6F22 9 Volt battery. AAA cells would be better.
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Offline Carrington

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Re: XJW01 Auto LCR meter review ($120 bench top LCR meter)
« Reply #17 on: April 21, 2014, 09:31:17 pm »
It runs on a 6F22 9 Volt battery. AAA cells would be better.
Well, nothing is perfect, or to taste everyone.  :)
My English can be pretty bad, so suggestions are welcome. ;)
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Offline kripton2035

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Re: XJW01 Auto LCR meter review ($120 bench top LCR meter)
« Reply #18 on: April 21, 2014, 10:28:46 pm »
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.

Offline dannyf

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Re: XJW01 Auto LCR meter review ($120 bench top LCR meter)
« Reply #19 on: April 22, 2014, 12:08:51 am »
Quote
Nice project to study.

The 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.
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Offline dannyf

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Re: XJW01 Auto LCR meter review ($120 bench top LCR meter)
« Reply #20 on: April 22, 2014, 12:17:02 am »
Quote
100KHz Version:

If 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.
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Online BravoV

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Re: XJW01 Auto LCR meter review ($120 bench top LCR meter)
« Reply #21 on: April 22, 2014, 02:56:47 am »
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.
« Last Edit: April 22, 2014, 03:00:09 am by BravoV »
 

Offline JacquesBBB

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Re: XJW01 Auto LCR meter review ($120 bench top LCR meter)
« Reply #22 on: December 17, 2014, 09:30:52 pm »
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.
Thanks

Jacques
 

Offline wblackledg

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Re: XJW01 Auto LCR meter review ($120 bench top LCR meter)
« Reply #23 on: July 09, 2015, 01:59:34 am »
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 work
somebody took a soldering iron and melted 110v into the back. (I guess sharpies are in short supply? )  :-DD

I tested some high end audio Elan caps against it, and this crappy meter
http://www.ebay.com/itm/new-Digital-LCD-Capacitance-Capacitor-LCR-Meter-Tester-Multimeter-20mF-200pF-/271874301855?pt=LH_DefaultDomain_0&hash=item3f4cf89f9f

I 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.
« Last Edit: July 09, 2015, 02:07:30 am by wblackledg »
 

Offline wblackledg

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Re: XJW01 Auto LCR meter review ($120 bench top LCR meter)
« Reply #24 on: July 09, 2015, 02:14:28 am »
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.
Thanks

Jacques

weighs about as much as a computer keyboard, but smaller. if you really want I can try and give you the actual weight.
 


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