An inexpensive multimeter combination: UNI-T UT125C and Aneng AN870 - Page 1
Forum section: electronics / testgear

author: AndrewBCN
author_rank: Frequent Contributor
timestamp: September 16, 2021, 04:41:06 pm
content: When on a limited budget, choosing a digital multimeter (DMM) is a surprisingly difficult decision, for various reasons, among others the vast choice of models from different brands in the low end.Also there are numerous, detailed reviews of high-end, extremely expensive DMMs, but when it comes to low-end DMMs, the "reviews" often consist of an "unboxing" and general comments on the functionality and ranges.Thankfully, HKJ here in this forum has a website with detailed reviews of a large number of both low end and high end DMMs, and I have selected and purchased two of the DMMs he has reviewed, mostly based on the information he provided.https://lygte-info.dk/info/indexDMMReviews%20UK.htmlIn what follows I will explain the logic of purchasing two DMMs instead of one, and the reason I have chosen the UNI-T UT125C and the Aneng AN870. But first the HKJ reviews:1. UNI-T UT125C :https://lygte-info.dk/review/DMMUNI-T%20UT125C%20UK.html2. Aneng AN870 :https://lygte-info.dk/review/DMMAnengAN870%20UK.htmlTotal Budget of 46€ (approx. $50) : 15€ for the UNI-T UT125C and 31€ for the Aneng AN870 (actually 26.50€ for the AN870 + 4.50€ for an extra set of leads). Shipping from China and VAT included in these prices.A few comments about these two very different DMMs and why - to me - they are complementary.UNI-T UT125CThis is a small 4,000 counts autorange handheld DMM with fixed (non-interchangeable) leads. The main features that caught my eye in HKJ's review are:1. It has rather decent input protection: 2 PTCs and 3 MOVs. It also uses a large ceramic fuse. Also the PTCs are shrouded in the unit I received (see attached picture).2. Despite its small size, the display is relatively large and very readable. There is also a backlight.3. It uses 2x AAA batteries with decent battery life, not the expensive and short-lived 9V batteries.4. It is independently certified and rated CAT III 600V. * (see note below)Upon receiving it, I noticed that the NCV detection is always working and at least for me, it works quite well. The plastics have a good feeling and the leads and rotary switch are OK, but not great.I noticed the unit I received is slightly different internally from the unit HKJ reviewed (it has an extra diode in the input section apparently, see D4-D5). In the hand, the UT125C feels like a solid little piece of equipment.Main usage for the UT125C will be "field use" around the house and occasionally when I have to measure high AC or DC voltages in my projects. If I would ever need to measure mains AC currents, I would buy an AC clamp meter.Aneng AN870This is a large 20,000 counts TRMS autorange handheld DMM. The main features that caught my eye in HKJ's review are:1. Decent accuracy in DC voltage ranges.2. Many functions.3. Uses 2x AA batteries, with decent battery life.4. Large, easy-to-read display with decent backlight (that stays on).5. Poor input protection (a single PTC and a pair of clamping transistors), but at least it has two decent size ceramic fuses. This DMM is not independently certified, so the CAT IV 600V rating is fake. In my opinion it should not be used for anything involving mains/high voltages.Upon receiving it, I noticed that the plastics have a rather cheap feeling and the included test leads are, quite honestly, total crap. So I bought a separate pair of inexpensive silicone leads with gold tip probes and these are very nice. The AN870 continuity detector is very fast and works well with the golden tip probes. I bought the golden tip silicone leads as recommended by Fungus here on the EEVblog forum. In the hand, the AN870 feels reassuringly heavy. Mine came with a simple pouch and a thermocouple probe.Main usage for the AN870 will be as a general purpose DMM for my DIY electronics / microcontroller projects.Why two multimeters?The logic here is to use the right tool for the right job while staying within a small budget of < 50€. The UT125C will be used for anything involving mains voltages (230V here in France) whereas the AN870 will be used for my small electronics projects where voltages rarely if ever exceed 20V.On a separate note, if my budget were around 210€, I would buy a Brymen BM869s which joeqsmith has stress tested and reviewed thoroughly.https://brymen.eu/shop/bm869sbut perhaps I would still buy the UNI-T UT125C to throw in the toolbox. Btw a replacement fuse for the BM869s costs as much as the UNI-T UT125c with shipping and VAT, which I find somewhat absurd.Attached some pictures, many more are available on HKJ's website. Picture 4 shows the difference in size between the digits on the UT125C and the AN870, as well as the silicone test leads that I purchased separately to replace the original crappy ones that came with the ANENG AN870. Picture 5 shows the internals of the AN870, which are almost identical to the one reviewed by HKJ (the 20A current shunt shape has changed, as far as I can tell).* Note about the independent certification of the UNI-T UT125COn the back of the UT125C we have the certification symbol and the Intertek name.I have confirmed that the UT125C has been independently tested and certified by Intertek, as can be verified here:https://ramuk.intertekconnect.com/WebClients/ITS/DLP/products.nsf/4c8700f3b75987a08525777700583333/1d393ddebcfb5489862586280014abff?OpenDocument

author: pcprogrammer
author_rank: Super Contributor
timestamp: September 16, 2021, 04:50:47 pm
content: QuoteA link to the leads you bought would be appreciated. Need new ones for an old DMM I have

author: AndrewBCN
author_rank: Frequent Contributor
timestamp: September 16, 2021, 05:30:23 pm
content: Quote from: pcprogrammer on September 16, 2021, 04:50:47 pmThey were very exactly these:https://fr.aliexpress.com/item/4001306288640.htmlBe sure to select the 20A Gold.Also note a number of sellers sell similar probe test leads.

author: Fungus
author_rank: Super Contributor
timestamp: September 16, 2021, 06:18:10 pm
content: Quote from: AndrewBCN on September 16, 2021, 04:41:06 pmBoth very comprehensive, as usual.Quote from: AndrewBCN on September 16, 2021, 05:30:23 pmYep, there's alotof sellers of those leads on Aliexpress.I haven't seen them with crocodile clips before.Beware that these leads aresharp, theywilldraw blood.You'll want to keep the little covers handy if you want to transport the meter or keep it in a case.

author: AndrewBCN
author_rank: Frequent Contributor
timestamp: September 20, 2021, 04:12:14 pm
content: Joe Smith (joeqsmith here in this forum) has a video where he reviews and transient-tests the AN860B, an earlier version of the AN870 with a very similar board layout. There are a few improvements of note in the AN870 vs the AN860B with respect to Joe's video:- The AN870 uses ceramic fuses, the AN860B used the cheaper glass fuses.- The current shunt in the AN870 is longer and should be able to dissipate more heat than the current shunt in the AN860B (although I still wouldn't use it for any measurements higher than 7~8A DC currents).- The PTC is larger than the one in the AN860B.On the other hand, the LCD backlight hotspot which Joe noticed is still very much there!The main IC in the AN870 is probably yet another variant of the very same Dream Tech DTM0660L (rumored to be a clone of the HY12P65) that ANENG uses in various DMMs in their lineup and used in the AN860B.Despite these changes I believe the AN870 would also fail during transient testing somewhere above 2kV, similarly to the AN860B. In other words: the CAT rating is fake and the AN870 should not be used for testing mains voltages indoors or outdoors.Also, for reference, floodbydust here in this forum has reverse-engineered the input stage of the AN8008, and it is probably very similar to the input stage of the AN870. See here:https://www.eevblog.com/forum/testgear/an8008-us-$19-10000count-1uv-0-01ua-0-01ohm-resolution-meter/msg1264186/#msg1264186

author: Fungus
author_rank: Super Contributor
timestamp: September 20, 2021, 04:41:12 pm
content: Quote from: AndrewBCN on September 20, 2021, 04:12:14 pmI don't think many people here would imagine otherwise but the Aneng 860B is still one of my favorite meters. In terms of measurement abilities and feel it's a winner. I also threw one in my case to go to Arduino class where lots of students abused it for a year or so doing low voltage DC and still looks/works like new.The very first post also says:Quote from: AndrewBCN on September 16, 2021, 04:41:06 pmThe meter you need to cast doubt on is the Uni-T, not the Aneng.

author: AndrewBCN
author_rank: Frequent Contributor
timestamp: September 20, 2021, 05:05:13 pm
content: Quote from: Fungus on September 20, 2021, 04:41:12 pmI think you recently wrote that "anecdotal data is not evidence" ?The AN870 does feel like it could provide years of reliable use on my workbench. What I like best about it is its high resolution (4 1/2 digits), the fast continuity check, the large LCD display, the batteries (2 x AA) and of course its very low price. However people considering buying an AN870 should realize that the included test leads are practically unusable, they'll end up having to pay for an extra set of test leads, just like I did. Not a big deal (the silicone test leads with golden tips cost 4.50€) but still annoying.Quote from: Fungus on September 20, 2021, 04:41:12 pmWell, I of course proceeded to measure AC mains voltage as soon as I inserted the two AAA batteries in the UT125C and it measured 231.6V (nominal 230V here in France) without any complaints. I also asked Joe if he could stress-test one (if he would ever get his hands on a UT125C) but he has already tested a UT139C which has very similar input protection as the UT125C, as far as I can tell.We'll see. My first (totally subjective) impression of the UT125C is quite good, anyways. For the very modest costand for my intended use, it was clearly worth purchasing.

author: Fungus
author_rank: Super Contributor
timestamp: September 20, 2021, 05:15:18 pm
content: Quote from: AndrewBCN on September 20, 2021, 05:05:13 pmTrue, but I'm not making anyextraordinary claimsso the standard of evidence is much lower.Quote from: AndrewBCN on September 20, 2021, 05:05:13 pmYou thinkthey'rebad? You should see the optional set of "modular" leads that the meter can come with.