XJW01 Auto LCR meter review ($120 bench top LCR meter)

[Yansi]

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).

[dannyf]

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.

No. 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.

[dannyf]

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.

[happydad]

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.

[Yansi]

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.

[Wh1sper]

I purchased this LCR Meter lateley.
https://www.banggood.com/DIY-Auto-LCR-Digital-Electric-Bridge-Resistance-Capacitance-Inductance-ESR-Meter-Kit-p-1113600.html
I'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.

[Specmaster]

I purchased this LCR Meter lateley.
https://www.banggood.com/DIY-Auto-LCR-Digital-Electric-Bridge-Resistance-Capacitance-Inductance-ESR-Meter-Kit-p-1113600.html
I'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.

I brought mine a few months ago, already assembled from here http://www.ebay.co.uk/itm/Auto-LCR-Digital-Electric-Bridge-Resistance-Capacitance-Inductance-ESR-Meter-New-/181367473225?hash=item2a3a580449:g:UogAAMXQeKNTOh0c and 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.

[Wh1sper]

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.html

Here comes the automatic Google Trans of the chinese Description, which was my input for the German Article.

LCR-3 digital bridge
Stalls:
Inductance 200mH - 2000H minimum resolution 0.1uH
Capacitance 200pF - 200mF Minimum resolution 0.01pF
Resistance 2000m?- 20M? Minimum resolution 0.1m?
 
Secondary display range:
Q: 0.000- 999.0
D: 0.000-9.999
?: -179.0- +179.0
 
 
Features:
? main display 1999.9 count, vice display 999.9 count ? measurement frequency: 100HZ / 1KHZ / 7.8KHZ
? measurement voltage: 0.2Vrms
? output impedance: 40?
? basic accuracy: 0.3%
?LCR automatic identification / manual measurement
? open / short circuit calibration compensation
 
Cs :
Capacitance parallel mode
Cs: Capacitance series mode
Lp: Inductance parallel mode
Ls: Inductance series mode
Rp: Resistance parallel mode
Rs: Resistance series mode

Secondary display:
Q: Quality factor
D: Loss factor
?: Phase angle
Rp: Equivalent Shunt
Resistance ESR: Equivalent Series Resistance
Xp: Equivalent shunt reactance
Xs: Equivalent series reactance
 
 
Operation Guide:
Press " menu ( MENU ) to enter the main menu
and press the " range ( the RNG ) " key to enter the calibration mode  ,  then pressing the  C key, the current key : ( Z0 of items) the calibration data will be cleared !!!
To restore the default accuracy of 0.5%
Can be calibrated to 0.3%
 
1, automatic measurement
When the instrument is turned on, the default state is auto recognition mode (AUTO), the default measurement frequency is 1KHz.
In automatic mode, the instrument automatically recognizes the impedance characteristics of the measured object, and automatically selects the series-parallel mode of the main parameters of L, C or R.
In the automatic measurement mode, the series-parallel mode depends on the impedance of the measured object. When the impedance is high (> 10K?), the parallel mode is selected and the impedance is low (<10K?).
 
2, L / C / R mode measurement parameters
1) Main parameter selection, in the power state default AUTO, press the "mode (X)" key parameters are selected as "AUTO ? AUTO-C ? AUTO-L ? AUTO-R ? AUTO"
Note 1: The series mode is "ESR", the parallel mode is "RP", Xs / Xp is activated only when the main parameter R (resistance) is active.
 
3, series and parallel measurement mode selection , in the corresponding main mode press the "value (R)" key, the parameters are selected as "AUTO- <C \ L \ R> ? P ? S ? AUTO- <C \ L \ R> ".
 
4, the measurement frequency, the bridge provides three frequency test points: 100HZ / 1KHZ / 7.8KHZ boot the default frequency of 1KHz, press the "frequency (F)" key can choose a different frequency point measurement "1KHZ ? 7.8KHZ ? 100HZ ? 1KHZ ".
 
5, open / short-circuit calibration compensation , measurement clip open or short-circuit state under the "zero (C)" key can be swept open / short circuit calibration compensation. (Measurement clamp open press the "zero (C)" key to scan the open circuit clear test clip short circuit by C key to do short-circuit clear)
 
6, advanced mode ?2004 screen? , press the "Save (L)" key in any measurement mode to enter this mode (manual mode), exit manual mode Press "Save (L)" key.
In the advanced mode mode, the "Range (RNG)" key is available and the range "40R ? 1K ? 10K ? 100K ? 40R" is switched.
The first line shows the following:
Manual mode identification, and serial identification, impedance - reactance
The second line shows the following:
Measurement frequency, main range, capacitance (inductance) measured value, Q value
 
7, calibration mode , press the "menu (menu)" key to enter the main menu. And then press the "rng" key to enter the calibration mode
To exit the calibration mode: Press the "menu" key to enter the main menu, and then press the "Mode (X)" key to return to the measurement mode.
In calibration mode, the parameter (Q), frequency (F), these two keys are selected for calibration items.
Mode (X), value (R), which is the + - calibration parameter value.
"Save (L)" key: save the calibration results, after calibration must press the "save (L)" button, otherwise the calibration results will not be stored.
"Zero" (C) key: Used to clear the value of the current calibration item.
Pressing 5 times in succession will load the default calibration value.
8. Relative measurement
In the measurement mode, pressing the"Parameter(Q)"key will record the current measurement and enter the relative measurement mode, press the"parameter(Q)"key again, or the mode switch, etc. Relative measurement. In the relative measurement mode, the sub-participant shows the relative error of the measured object at the recorded value, and the representation is the percentage.
The range is:-99.9%to+ 99.9%
 
 Note: In calibration mode, mode (X), value (R) long press can quickly increase or decrease the calibration value.
 
 
?

Features
measurement method
frequency
Stalls
Minimum resolution
Capacitor Block C
Cs / Cp
100Hz
2000.0pF ~ 200.00mF
0.1pF
1KHz
2000.0pF ~ 20.000mF
0.1pF
7.8KHz
200.00pF ~ 2.0000mF
0.01pF
Inductance block
Ls / Lp
100Hz
2000.0mH ~ 2000.0H
0.1?H
1KHz
2000.0mH ~ 200.00H
0.1?H
7.8KHz
200.00mH ~ 20.000H
0.01?H
Resistance file R
Rs / Rp
100Hz
2000.0m? ~ 20.000M?
0.1m?
1KHz
2000.0m? ~ 20.000M?
0.1m?
7.8KHz
2000.0m? ~ 2.0000M?
0.1m?
 
 
LCD 2004 screen can display 20x04 or 80 characters at the same time.
 
Turn on the power supply first screen display LCR digital bridge Author information:
 
?
XJW, PUTIAN, 2012
 
And then into the working state:
 
2004 screen
?
 
?
LCD2004 screen physical map
?
 
 
 
Finished plate has been calibrated to 0.3% , if necessary , can be self-calibration:
setting menu:
Press the "menu" button to display the following:
?
?
Under this screen: Return to the measurement mode Press the "Mode (X) " key. To enter the calibration settings Press the " Rng " key.
Calibration default: press 5 times C key (just 5 times) to restore to the default value, then press the L key to save. The first calibration must be restored to the default value.
(Note: Press " menu ( MENU ) key to enter the main menu and press. " Range ( the RNG ) " key to enter the calibration mode  ,  then pressing the  C key, the current calibration data items will be cleared !!!)
The following items are displayed in the calibration settings:
 
"Z0: 000"?100Hz zero calibration? is calibrated to 0
"Z1: 000" [1kHz zero calibration] is calibrated to zero
"Z2: 000" [7.8 kHz zero calibration] is calibrated to zero
"R1: 40" [ V / I converter lower arm  resistance 40R calibration ] access 40R resistor, calibration to resistance nominal value 40 ohms
"R1X: 40" [40R phase] is calibrated to phase 0
"ak: 25" linear calibration [AD]                 12 years . 1 January STC film AK values . 5 to 30 between. Access 25 ohm resistance calibration (normally set to zero)
"R2: 1k" [ V / I converter lower arm   resistance 1K calibration ] access 1K resistance, calibration to resistance nominal value 1K
"R2X: 1k" [1k phase] is calibrated to phase 0
"R3: 10k"?V / I converter lower arm  resistance 10K calibration? access 10K resistance, calibration to resistance nominal value 10K
"R3X: 10k" [10k phase] access 10K resistor, transferred to the capacitor as the value of open-circuit residual capacitance. (0.1p-3.5p if the unit is H please hold down the X key, one will become a 0.1P-3.5p
"R4: .1M" [ V / I converter lower arm resistance 100K calibration ] access 100K resistance, calibration to resistance nominal value 100K
"R4b: .1M " [7.8kHz frequency 100k file amplitude calibration] access 100K resistance, calibration to the nominal value of resistance 100K
 "R4X: .1M"?100k phase? access 100K resistor, transferred to the capacitor as the value of open-circuit residual capacitance. (0.1p-3.5p)
"G1: 3k" [op amp 3 times gain calibration] access 3K resistance, calibration to resistance nominal value 3K
"G1X: 3k" [3 times the file phase] access 3K resistance, transferred to the capacitor as the value of open-circuit residual capacitance. (0.1p-3.5p)
"G2: 9k" [op amp 9 times gain calibration] access 9K resistance, calibration to resistance nominal 9K
"G2b: 9k" [7.8kHz frequency 9 times the file amplitude calibration] access 9K resistance, calibration to the nominal value of resistance 9K
 "G2X: 9k" [9 times the file phase] access 9K resistor, transferred to the capacitor as the value of open-circuit residual capacitance. (0.1p-3.5p)
"PhX: 1k" [1kHz below phase calibration] is recommended to zero           
 
After entering the calibration menu, use the Q (left) or F (right) keys to toggle the parameters. The X and R keys are plus, minus the number.
PhX , R4b , G2b is a special calibration item, it is recommended to zero.
Calibration Order: Black Item Red Item Blue item .
 
After calibration is complete, be sure to save the L key. And then press the "menu" button, return to the main menu, press the "mode (X)" key, exit.
Note: In calibration mode, mode (X), value (R) long press can quickly increase or decrease the calibration value.
?

Tel: 18954185369

QQ: 469968260

E-Mail: freefm@126.com

[Radiohead]

I found the translated schematic by BlueSkull in this thread https://www.eevblog.com/forum/projects/chinese-lcr-meter-schematic-with-stm32-questions-can-someone-translate-please/msg832297/#msg832297 and 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.pdf while search for RLC meter designs. Of course no references to either of them.

[WhichEnt2]

Can anyone tell me about the 2.7MOhm parameter (attachment)? Avaliable docs are not clearly describe this.

[buildafriend]

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 OP

Okay soo..  there's a menu button. If you hold it down It says:
LCR Set Options
Exit: X   Ver:5.5
There is no X button So restart it via the power switch and pretend I don't need to check that. Thanks for the options 

I 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 Hc

Lc = 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 correct

Then 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 / ESR

QTY / +/- %

Freq / *picture of sine wave*

What do all of these buttons do?

[Yansi]

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.

[Specmaster]

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.

[Yansi]

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.

[buildafriend]

Bitching? There's no bitching here man 

I'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.

[WhichEnt2]

Lc = Loading capacitor? Inductive Capacitive? Left Channel? Low?

Yep, some sort of low.
Check the keysight impedance handbook: https://literature.cdn.keysight.com/litweb/pdf/5950-3000.pdf

[buildafriend]

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,

[Specmaster]

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?

[WhichEnt2]

They usually use 120 or 100 Hz for dissipation factor and 100 kHz for ESR.

[Specmaster]

They usually use 120 or 100 Hz for dissipation factor and 100 kHz for ESR.

Just 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 [emoji83]

[buildafriend]

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.

[AG7CK]

 

Impedance  = Voltage / Current = Potential / Current

(Force) Current High and Low : Hc, Lc
(Sense) Potential High and Low : Hp, Lp

The 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 who already know how to use a generic LCR meter already (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.

 
 

[WhichEnt2]

They usually use 120 or 100 Hz for dissipation factor and 100 kHz for ESR.

Just 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 [emoji83]

I checked it just now on random vishay cap series, as you.

http://www.vishay.com/docs/28420/160rla.pdf

[AG7CK]

 

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.

 

[Specmaster]

And which manuals would they be?