Need a handheld DMM just to measure AC/DC current - Page 1
Forum section: electronics / testgear

author: IDEngineer
author_rank: Super Contributor
timestamp: April 07, 2019, 03:08:05 pm
content: I know this sounds like a silly question, but after slogging through comparisons on TEquipment and Saelig and such I thought to just ask the collective wisdom here. I can't be the first to need something like this.I already have multiple DMM's, but the better ones have very low current ranges and the higher current ranges are on cheap low-quality DMM's that I use as throwaways, give to friends in an attempt to make them more self-supporting, etc. I also have current probes for the scopes but breaking out one of those and a scope to take a quick current measurement often seems like overkill and isn't very portable. A bench meter also isn't portable.So I'm thinking to just pick up a good quality DMM that has reasonable AC/DC current ranges. Or maybe even a dedicated handheld current meter if such a thing exists. I'm not talking a clamp meter, I mean one that you put in series. Range from ~10A down to sub-mA would be nice, with emphasis on the lower end.Do I default to a Fluke 87-5 just to get its current ranges? Or is there something better for this narrow use case?Thanks for any recommendations!

author: Brutte
author_rank: Frequent Contributor
timestamp: April 07, 2019, 03:42:34 pm
content: I am not sure what measurement you need that for but for me (embedded) it is essential to measure for example current draw during development.So if this is for lab curret measurement I would highly recommend a non-portable desktop version with analog gauge. I use a big readable analog display where I can observe real-time what is going on. Digital is not suitable for that. I do not care if that is 5mA or 4.99mA so a 2% is ok for me. But it must run for weeks, reliably.Also same applies to bullshit detectingdigital bullshit detectors are just not suitable for this kind of job.And if you need to measure AC sinusoidal currents - I would not bother with anything else but the clamp meter. It is no contest when you just clamp on a wire, no cutting of a circuit. On clamp meter if you need to switch the range you can just wrap a wire 10x and you get 10x gain.

author: IDEngineer
author_rank: Super Contributor
timestamp: April 07, 2019, 04:16:02 pm
content: Quote from: Brutte on April 07, 2019, 03:42:34 pmYes, most of the time this is for embedded development. But once in a while I need it for in-the-field situations too.Like most test equipment, I keep putting off this purchase but yesterday is a good example of what tipped me over. My son, who is an internationally ranked drone racing pilot, was having trouble diagnosing a problem on one of his aircraft. He needed to see which, if any, of the boards were pulling excessive current beyond the few 10's of mA that each one should be drawing. Yesterday this was at home, but when we're on the road (including overseas) we often set up a nice little rework station right on a park bench wherever that course happens to be set up. Portable scope, Hakko station, a portable power supply I built, etc. We're limited in what we can carry on the plane so tools have to be small and rugged.That's why I'm favoring a handheld meter for this task. Sure, a bench device is probably more accurate, but it's large and heavy enough that it will get left home and then we won't have it when we need it. Conversely, at home that same handheld meter will work just fine for embedded development. It sounds like you need to monitor currents for very long, continuous durations but my projects don't need that so my use case is different than yours.I agree that absolute accuracy isn't super important. A couple of percent is more than sufficient for what I'm doing. Often I'm comparing different current levels rather than recording absolute measurements so a couple of percent doesn't hurt anything.

author: Cnoob
author_rank: Regular Contributor
timestamp: April 07, 2019, 04:30:14 pm
content: If size is important then take a look at Brymen 23* and 25* series. They have 10A and uA ranges.https://brymen.eu/product-category/multimetry/Note 23* series does not have bar graph display. 25* series does.

author: David Hess
author_rank: Super Contributor
timestamp: April 07, 2019, 06:50:13 pm
content: Higher end digital multimeters have a more complete set of AC/DC current measurement ranges. Start checking datasheets.

author: IDEngineer
author_rank: Super Contributor
timestamp: April 07, 2019, 07:19:04 pm
content: Quote from: David Hess on April 07, 2019, 06:50:13 pmI said:Quote...by which I meant I had checked the specs on countless meters, both those published on the websites named and by going to the manufacturer's websites. You're right, there's plenty of options if I just want to throw money at the problem. That's why I also said:Quote...because I hoped that someone(s) might have a specific suggestion on the topic beyond the obvious default of "go buy a high end piece of equipment". I was thinking there might be a little known current meter, or "I always use my Fluke for general purpose stuff but I've found the Acme XYZ123 works really well for the specific task of measuring current".If nobody has any specific suggestions I'll probably just default to a Fluke 87-V. I just don't want to default to "spend lots of money on the known name brand" and then LATER find out there was a better option.

author: Fungus
author_rank: Super Contributor
timestamp: April 07, 2019, 11:25:45 pm
content: Quote from: IDEngineer on April 07, 2019, 07:19:04 pmBy that I assume you own some sort of Fluke electrician's meter, no uA range.Quote from: IDEngineer on April 07, 2019, 07:19:04 pmAlmost any meter will do that, there's $25 Chinese meters with nA abilities.I second the "Brymen" recommendation. If you buy a nice Brymen you'll probably never look at a Fluke ever again. Even their monsterBM869Sis still half the price of a Fluke 87V.

author: IDEngineer
author_rank: Super Contributor
timestamp: April 07, 2019, 11:56:12 pm
content: Quote from: Fungus on April 07, 2019, 11:25:45 pmThe Fluke I was thinking of is a Fluke 16, which has a current range of just 200uA with 100nA resolution. Great for very small currents (which is what I use it for) but anything in the 10's of mA and up is too much.QuoteInteresting! Two votes for a brand I've never seen anywhere nor heard of before this thread. I'll definitely look more closely at them. When I went to their website they seemed to be a really budget device so I didn't pay too much attention. Thanks!EDIT: Where can you get spec sheets on Brymen meters? That brymen.eu link only gives the roughest of idea what each model will even do.

author: kj7e
author_rank: Frequent Contributor
timestamp: April 08, 2019, 12:04:08 am
content: Quote from: IDEngineer on April 07, 2019, 11:56:12 pmBrymen DMM's are solid and quality items. If I didn't already have two Fluke 189's and a 289 I would pick up a BM869S in a heartbeat.Docs and sepcs can be downloaded from TME's page here;https://www.tme.eu/en/details/bm869/portable-digital-multimeters/brymen/bm869s/

author: Fungus
author_rank: Super Contributor
timestamp: April 08, 2019, 12:05:30 am
content: Quote from: IDEngineer on April 07, 2019, 11:56:12 pmEvery meter has a "data sheet" in the meter's "downloads" section.eg. The 869s:https://brymen.eu/wp-content/uploads/biall/102092/102092.KARTA_EN..2015-07-09.1.pdf

author: IDEngineer
author_rank: Super Contributor
timestamp: April 08, 2019, 12:52:10 am
content: Quote from: Fungus on April 08, 2019, 12:05:30 amTrouble was, I couldn't find the Downloads section. I had looked under "Support", etc. But there it was, cleverly hidden on each product page! Silly me.Wonder if there's a US distributor?Reading now....

author: tautech
author_rank: Super Contributor
timestamp: April 08, 2019, 01:00:59 am
content: Check Joe's videos if you want good info on Bymens.He's quite a fanboy of their stuff:https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/

author: Fungus
author_rank: Super Contributor
timestamp: April 08, 2019, 01:25:51 am
content: Quote from: IDEngineer on April 08, 2019, 12:52:10 amIn the USA they're sold under the "Greenlee" brand:https://www.greenlee.com/us/en/digital-multimeters

author: joeqsmith
author_rank: Super Contributor
timestamp: April 08, 2019, 01:35:25 am
content: Quote from: tautech on April 08, 2019, 01:00:59 amWhen if come to Brymen, I let the data do the talking..

author: Fungus
author_rank: Super Contributor
timestamp: April 08, 2019, 01:51:46 am
content: Quote from: joeqsmith on April 08, 2019, 01:35:25 amJust so you know: This is the guy who built a special machine to turn the dial full range 50,000 times to see if it wore out (it didn't)

author: kj7e
author_rank: Frequent Contributor
timestamp: April 08, 2019, 02:00:21 am
content: Quote from: Fungus on April 08, 2019, 01:51:46 amYet we still don't know how many licks it takes to get to the center of a tootsie pop.

author: Fungus
author_rank: Super Contributor
timestamp: April 08, 2019, 07:29:22 am
content: Quote from: kj7e on April 08, 2019, 02:00:21 amJoe certainly failed us there.

author: Cnoob
author_rank: Regular Contributor
timestamp: April 08, 2019, 08:09:12 am
content: QuoteThe Brymen.eu sited does have manuals and data sheets for each meter.Click on a particular meter, click on downloads then click on the word /s data sheet or manual.

author: joeqsmith
author_rank: Super Contributor
timestamp: April 08, 2019, 12:18:57 pm
content: Quote from: Fungus on April 08, 2019, 07:29:22 amI would need to come up with some sort of realistic test procedure. Then design some sort of licking, sucking test fixture. Wait, I have an idea!!

author: tooki
author_rank: Super Contributor
timestamp: April 08, 2019, 06:23:49 pm
content: Does it involve giving me the tootsie roll pops to consume? ::raises hand::(I like the cherry and grape ones, please! :p)

author: Fungus
author_rank: Super Contributor
timestamp: April 08, 2019, 07:37:13 pm
content: Quote from: joeqsmith on April 08, 2019, 12:18:57 pmIf you can design a battery powered device that does all that then I have an idea for a kickstarter.

author: BillB
author_rank: Unknown
timestamp: April 08, 2019, 10:49:16 pm
content: Quote from: joeqsmith on April 08, 2019, 12:18:57 pmDon't bother. It's already been solved. Three. It takes three licks.