YR2050 Milliohm Meter High-Precision Handheld DC

[enut11]

Good milliohm meters can be very expensive, and, the older they are the more they cost!

Found this relatively cheap (~$60US) meter on eBay and was wondering if anyone has tested one.
It certainly has a lot of digits and, from what I see on the back label, the test current appears to be up to 500mA? EDIT - see next reply.

Brief specs from the listing below:

- Resolution 120000
- Temperature drift: ±100ppm (10~40 ℃)
Gear     Minimum position       Accuracy indication ±(reading%+range%)
1Ω           0.01mΩ                         ±(0.12%+0.03%)
10Ω         0.1mΩ                           ±(0.08%+0.02%)
100Ω      1mΩ                               ±(0.08%+0.02%)
1KΩ        10mΩ                            ±(0.10%+0.03%)

https://www.ebay.com.au/itm/314044912094

[enut11]

I found another listing which has a copy of the manual showing the test current for various ranges.

https://www.ebay.com.au/itm/354995090853?_trkparms=amclksrc%3DITM%26aid%3D1110006%26algo%3DHOMESPLICE.SIM%26ao%3D1%26asc%3D20201210111314%26meid%3Db6256c080fd14ca09072b1538c48b51d%26pid%3D101195%26rk%3D1%26rkt%3D12%26sd%3D314044912094%26itm%3D354995090853%26pmt%3D1%26noa%3D0%26pg%3D4429486%26algv%3DSimplAMLv11WebTrimmedV3MskuWithLambda85KnnRecallV1V2V4ItemNrtInQueryAndCassiniVisualRankerAndBertRecallWithVMEV3CPCAuto%26brand%3DUnbranded&_trksid=p4429486.c101195.m1851&amdata=cksum%3A354995090853b6256c080fd14ca09072b1538c48b51d%7Cenc%3AAQAIAAABYObhgc4Nk8%252BdtAwOww4FKLaj%252FQ5qqgDlQCuqZA43WcPFUWDERCUugbbOk7XQv0JXlBfqCg2xKF3WcPghxGMFw2oSlXvfExEaMYr7I7LmrHcP6czY1wIMt0ORyKiCWt95xldincyyBx3g%252BNDW%252B%252FhWUgTaBhK6xAm%252BJIbCOMehu%252BdwAKIos3lSV2cWI%252FfMjOs%252Fi0yQMRy3Wk2yf0yEUJyGzN4hArsdKH1LckEzGK9TWa5JzJ4%252FcrjcMmUenOReljRwpnqh%252Bug3WW5L3OxFmrBPNJdurtk%252FVo3ow5l1c3tXXqHhRtfD%252BUFtDeWTDzJkHjkUw5nO%252FvVQGLxbesKo211fiHFl63rykbb4AGMfUfGij8UB3%252BnVv6ZpXSQ5q55i%252BaidGhPsUYWcRYXsDzpapOw6Pn3qrZlKCadIBFlj3FPNY8OABteN1Ssyg0KYHEW4talyRLNFVdi2CqhJp7kOARqDUQw%253D%7Campid%3APL_CLK%7Cclp%3A4429486

[enut11]

YT video feedback says there is an english manual available - somewhere!

The YR2050 Modes:
1.general mode; 2.checking mode; 3.background setting; 4. energy saving setting; 5.up down limited alarm;6.port setting; 7.calibrate/adjust; 8. restore calibration/adjust; 9.contrast; 10.resistance ratio setting

Still looking for an interior shot to see if it might be hackable...

[UK]

Hey! It's a nice milliohm meter, I use it frequently.
I'm currently out of town, but on Tuesday I could take some pictures of its insides... of course if you're not in a rush to buy this unit today

[thm_w]

You can find a few short reviews here: https://www.aliexpress.us/item/2255800323558045.html
Sounds like the menus are in chinese only.

video: https://www.youtube.com/watch?v=h4MDwn6nUH4

What are you planning to hack on it, the test current?

[enut11]

I would like to be assured that the test current is adequate and not excessive.
Also interested in verifying the stated accuracy which seems to be better than some more expensive units.
There must be some Vref in there and it would be nice to check that out.

[alm]

I found another listing which has a copy of the manual showing the test current for various ranges.

I don't see test current, just power consumption. There may well be a DC-DC convertor that's driving the current source.

Test current is generally not so important. What's important is dissipation in the DUT (I^2*R) and the voltage drop. For contact resistance measurements, in which you don't want the test signal to break through any oxides, since that's what you want to measure, the voltage is usually kept under 20 mV. Otherwise whatever voltage doesn't damage your DUT will work. For in-circuit measurements it would be useful if the voltage was below a diode drop.

There must be some Vref in there and it would be nice to check that out.

Probably nothing special for 0.08%.

[UK]

I would like to be assured that the test current is adequate and not excessive.

Regarding the test current for its different modes, I've found it in my notes:
1 Ω - 97.88 mA
10 Ω - 9.874 mA
100 Ω - 0.989 mA
1 KΩ - 0.097 mA

All measurements was done with my trusty UT171B.
Hope that helps you a bit while I'm traveling.

[enut11]

Thanks @UK. That is certainly what I wanted to know. These are not nice round figures so I am guessing the 0.08% calibration is done through saved constants.

When you get home, could you also check the compliance voltage?
enut11

[UK]

I've already measured it after buying the unit... and if I remember correctly it was about 1-2 mV.
But anyway I check it again for each mode.

[alm]

I've already measured it after buying the unit... and if I remember correctly it was about 1-2 mV.

How can ~100 mA through 1 Ohm be limited to 2 mV unless it's a constant voltage instead of a constant current source?

[enut11]

Need to measure open circuit voltage of test leads. Should be several volts.

[UK]

Of course, I've measured it with closed clamps. Since the seller said in capital letters that it is designed to measure only passive components and can be easily damaged by any powered circuit... since I haven't it principal circuit, so that's why I do not want to throw it into the bin just out of curiosity.

Hope you'll be happy with the taken photos. Chinese manufacturing conspiracy makes me sad with all these unmarked ICs.

Also, have to say its plastic shell is not the worst I've seen, but it definitely can be unscrewed only two or three times at max. 

[arturmariojr]

I wrote a manual in portuguese for it.
I hope it is better than the chinese one!

[enut11]

Of course, I've measured it with closed clamps. Since the seller said in capital letters that it is designed to measure only passive components and can be easily damaged by any powered circuit... since I haven't it principal circuit, so that's why I do not want to throw it into the bin just out of curiosity.

Hope you'll be happy with the taken photos. Chinese manufacturing conspiracy makes me sad with all these unmarked ICs.

Also, have to say its plastic shell is not the worst I've seen, but it definitely can be unscrewed only two or three times at max. 

Thanks @UK. Nice pix showing lots of detail. Single lion cell may limit the compliance voltage unless there is an up-scaler. In any case, measuring the open circuit test lead voltage with a DMM will not damage the device.
enut11

[enut11]

I wrote a manual in portuguese for it.
I hope it is better than the chinese one!

Thanks @arturmariojr. Yes indeed, it is easier to understand than Chinese.
I have downloaded the file and now looking for an MSword translator from Portuguese to English.
The front panel button labels can easily be overlaid in English.
enut11

[UK]

I have downloaded the file and now looking for an MSword translator from Portuguese to English.

Maybe I'll help you a bit since I already have it but only in the picture format.

[arturmariojr]

Hey, thanks a lot!

But has anyone ever studied a way to translate internal software? With paper manual or not, is very difficult to work with it with software in chinese...

A great equipment, but I think twice before using it!

[UK]

There no translation is needed practically.

In 95% of cases, you will use only the 1st menu item (resistance measure), and possibly 5% of the 2nd (wire measure) where both screens are without any Chinese characters. 4th (battery saving) and 9th (contrast) you will set only once after buying, and literally 9th is some kind of useless setting because the one acceptable value for contrast is 5 (from the 0-9 range). Then menu items 6th, 7th, and 8th are not even active... assume they are for dev purposes. And finally, the 10th just contains a ton of calibration values.

[DaneLaw]

I have downloaded the file and now looking for an MSword translator from Portuguese to English.

Maybe I'll help you a bit since I already have it but only in the picture format.

Thx - will definitely be a helping hand, as it's still Chinese language variants being sold, as far as I can tell.. doesn't look to be any newer revision of the YR2050 milliohm meter.?
What is the general feedback on these Yaorea YR2050 milliOhm units ??
at around 32 euro incl. both delivery & 25%EUVAT (early 2024 prices) it's not like milliohm meters are hanging on the trees for a self-contained display unit in that lower pricebracket..

[Kean]

What is the general feedback on these Yaorea YR2050 milliOhm units ??
at around 32 euro incl. both delivery & 25%EUVAT (early 2024 prices) it's not like milliohm meters are hanging on the trees for a self-contained display unit in that lower pricebracket..

I posted some tests of my YR2050 with some 0.1% and 0.01% resistors.
See https://www.eevblog.com/forum/testgear/absolute-best-multimeter-test-leads-very-low-resistance/msg5269221/#msg5269221

*****
Also, unlike the YR1030 which is available as YR1035 with a better connector for the test leads, the YR2050 only seems to be available with the test leads using a USB connector.

[DaneLaw]

What is the general feedback on these Yaorea YR2050 milliOhm units ??
at around 32 euro incl. both delivery & 25%EUVAT (early 2024 prices) it's not like milliohm meters are hanging on the trees for a self-contained display unit in that lower pricebracket..

I posted some tests of my YR2050 with some 0.1% and 0.01% resistors.
See https://www.eevblog.com/forum/testgear/absolute-best-multimeter-test-leads-very-low-resistance/msg5269221/#msg5269221

*****
Also, unlike the YR1030 which is available as YR1035 with a better connector for the test leads, the YR2050 only seems to be available with the test leads using a USB connector.

Yes, I have seen your post Kean, thx.
My impression so far is that the YR2050 is a decent milliohm meter, as long as you have its price in mind & the lack of contending alternatives in this lower-end price bracket for a stand-alone unit, unless you wanna build one yourself..

So far I have only seen the model with the USB to Kelvin clamp interface for the YR2050 series, and not the screw-terminal even though the molding from UK's pictures is clearly optimized for one in the bottom, but seems its a housing that are used on numerous models..

[DaneLaw]

My YR2050 arrived a few days ago, and my first impressions are positive.
I purchased my unit directly from what seems to be their official sales channel.
Arrived in a double box with Yaorea branded packing tape.
The build quality is better than what I had expected for a price under 35 US (incl. both free delivery and 25% EUVAT) the housing seems rigid and the 4 leads are silicone wires with gold-plated kelvin clips.

The biggest con is obviously the Chinese language.
My unit arrived with software vers. 1.2209
It came with an 8-page English user manual that Yaorea now seems to incl. for western buyers,  but it does leave a lot to be desired for when you down into the sub menu's.

Instead turn to Google's Translate app.
Will post it here the relevant parts of the menu where the Chinese text are in play and things ain't obvious, so I can look it up when in doubt about the settings.

* Menu 10 (Res settings) from segment 13 to 20 are not valued with substances (13-20 customizable) .
Adjusted my screen backlight setting (menu3) to 60 sec delay so it doesn't turn off so fast & screen brightness to 55%.
Your null your value with "HOLD" button.. a short press equals HOLD and a long press equals nulling (it will show a U)

[enut11]

Thank you @DaneLaw. You have done many YR2050 owners a great service
enut11

[ass20]

i analize photo of yr2050

U14 U13 AD7705/7706 or  TM7705/06 TM7707/08 it is need Quartz 2.4576 mHz  Y2
D15 tl431
U1 STM8L151C6+
U4 LM321
U17 uln2003

J5 swim connector for flash U1

U19 U22 battery protection