Author Topic: First DMM? (Read 7661 times)

GigaJoe · « **Reply #25 on:** July 12, 2018, 07:07:19 pm »

Something $20 cheap, thing is .... later on you will figure-out needs , like better precision, or need a bench one with 5.5 or so or need autohold, need min/max or math , need bar graph, transistor measure , need something else ....

as a second moment: by mistake you may measure current in the wall plug, (had happens with me when I measure transformer parameters ... 2 DMM dead , cant fix it ...)

So i have a few disposable for $10-$20 it works well for 95% , the rest 5% covers by 5 or 6 digits bench one ... Another positive and some fun thing, change a quartz till it stable , some of them going up to 4-5 times faster, arranging range in eye blink

- I HATE slow multi-meter, unless it 6-7D ...

Doctorandus_P · « **Reply #26 on:** July 13, 2018, 12:02:52 am »

The Brymen meters have about the highest performance / quality you can get for 1/2 or 1/3 the price of a Fluke.
The Aneng meters are a very nice addition for electronics.
You always want more than 1 multimeter.
For example for measuring input and output voltages / currents fo a circuit.
Use one to keep track of the temperature of a transistor, while using another meter for who knows what.
If you are in doubt of the quality / accuracy of your DMM, you can use the second meter as a check.
You can use 1 DMM to check if the other has blown a fuse.
You can use 1 DMM to check input impedance etc. of another DMM.

The Aneng AN8009 (EUR 23 From Ali / Ebay) has a very generous amount of ranges.
The GreenLee meter mentioned earlier in this thread are rebranded Brymen's.
Some of the "Voltcraft" meters are also rebranded Brymens, (or UTi).

A DMM that beeps at me when the switch is in Volt position and the probes are in an Amp bananabus has saved me multiple times from blowing up my DMM.

xani · « **Reply #27 on:** July 13, 2018, 02:24:42 am »

Quote from: rhb on July 12, 2018, 04:22:02 pm

Quote from: xani on July 12, 2018, 11:24:58 am
Quote from: rhb on July 12, 2018, 03:14:01 am
Not sure where you live. But if you're in the US I suggest you buy a pack of gum at Harbor Freight and get a free DMM. With a cal they are good to better than 0.1%. And you can do the cal with some fresh batteries. All you need is the right coupon.
Life is too short for non-autoranging DMM . Also non-fused 10A range is something I'd avoid for someone that's just starting. If I got one for free sure I'd toss it in a toolbox as spare, but I woudn't want to pay for one

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The test probes are fragile, but a bit of hot melt glue where the wire goes into the probe is supposed to solve that.
I think that's all cheapish meters, good probes cost more than them for the most part

The 10 A range is fused. These are the modern equivalent of a Fluke 8000A except for not being rated to 1200 V. Beginners should not be playing with high voltages, so that hardly matters.

Is it ? On picture you attached shunt seems to go directly from COM to 10A., just like on other types of it. I did saw some other teardown that did seem to have it separate, so it might depend on model.

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These are the modern equivalent of a Fluke 8000A except for not being rated to 1200 V.

They look like same kind of meter I've used 20 years ago when I was a kid (well ones like that[/url;] ). Those didn't had 10 A range fused either.

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A beginner should be conscious at *all* times of what they expect the meter to read. A manual ranging meter encourages developing safe work habits. Autoranging meters tend to encourage just poking the probes in. That can get very spectacular if it's a CRT or microwave oven HV section no matter what DMM you're using.

If someone sets manual ranging meter to highest range and poke microwave or CRT, result will be as bad.

I don't really see a value in manual ranging (and you can do that on auto meter anyway if you really need), just adds to annoyance when probing unknown circuit. Fine for a cheapie (for price of HF meter you get amazing deal all things considered) but IMO getting anything above $30 with manual ranging is pointless.

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A well equipped electronics test bench is not cheap. I've got more of the HF units that I can count (or find). I've had only one fail. A 34401A certainly meets the OP's requirements, but I think all would agree it's rather overkill for a beginner.

The HF DMMs are one of the few Chinese T&M devices I don't dislike.

By the time you add up a DMM, DSO, AWG and PSU it's not cheap. You can fix a lot of things with just a DMM, but you *really* need to know what you're doing to be able to do that.

I just thought I should point out that a DMM is like your first shot of heroin. After that you want more. The TEA thread is testimony to that problem. So buying more than you need at any stage is questionable. And it's pretty hard to beat free.

Agreed. If I had $150 to spend on beginner's T&M I'd definitely not burn it on meter. Just cheap meter + used analog scope (or, in case of digital, cheapo logic analyzer) would be WAY more useful than $150 meter

Mr. Scram · « **Reply #28 on:** July 13, 2018, 02:29:51 am »

I'd argue going for the BM257 rather than the BM235. The bar graph is a good feature to have and the extra connectivity could be useful is that tickles your fancy. The latter could be considered superfluous, but a bar graph is a very useful tool and helps understanding what's going on more easily.

Lightages · « **Reply #29 on:** July 13, 2018, 02:41:41 am »

I will repeat the recommendation for a BM257S. You are unlikely to need anything better for a long time and unlikely to find anything better for the price.

GigaJoe · « **Reply #30 on:** July 13, 2018, 03:29:39 pm »

when I look at 257S, that what i don't like: AC voltage 60mV / 1000V ±(1.0%+5) @ 50-400Hz; 400Hz - really low , it more like electrician meter ...
seems only 860, 820 running to 20Khz .. 869 - to 100Khz

https://www.welectron.com/Brymen-BM867s-Multimeter_3 150 euro - consider , 5.5D ; precision, wide AC freq, bargraph, logging to PC, ...

rsjsouza · « **Reply #31 on:** July 13, 2018, 04:03:01 pm »

In addition to the Brymen/Greenlee (which I love) and since you are in the US, Home Depot has quite decently priced meters from Klein. The MM600 and MM700 are built-to-last meters with many features.

mtdoc · « **Reply #32 on:** July 13, 2018, 05:04:07 pm »

Quote from: GigaJoe on July 13, 2018, 03:29:39 pm

when I look at 257S, that what i don't like: AC voltage 60mV / 1000V ±(1.0%+5) @ 50-400Hz; 400Hz - really low , it more like electrician meter ...

Testing my BM257, I get 1% accuracy up to 1kHz with a 1 Vrms sine wave and up to 20kHz at 7 Vrms.

In reality I rarely ever need to measure high frequency AC amplitude and I doubt the OP does either at this point. Of course there are always trade offs unless you have unlimited funds.

The BM867 falls outside of his budget.

FWIW, in addition to the BM257 I own a Fluke 87V, Keysight U1252b, EEVBlog 121GW, 3 bench meters and some cheaper handhelds and yet the BM257 is my most used meter. It has all the functions and enough resolution and accuracy for 99% of what I do. Granted I am a hobbyist, not a professional EE, but so is the OP.

Gizzygone · « **Reply #33 on:** July 13, 2018, 05:10:42 pm »

Quote from: rsjsouza on July 13, 2018, 04:03:01 pm

In addition to the Brymen/Greenlee (which I love) and since you are in the US, Home Depot has quite decently priced meters from Klein. The MM600 and MM700 are built-to-last meters with many features.

I was curious about the Klein ones.... I have plenty of Klein tools that I love, but I wasn’t sure if their DMM options were anything worth looking into.

rsjsouza · « **Reply #34 on:** July 13, 2018, 07:44:59 pm »

Quote from: Gizzygone on July 13, 2018, 05:10:42 pm

Quote from: rsjsouza on July 13, 2018, 04:03:01 pm
In addition to the Brymen/Greenlee (which I love) and since you are in the US, Home Depot has quite decently priced meters from Klein. The MM600 and MM700 are built-to-last meters with many features.

I was curious about the Klein ones.... I have plenty of Klein tools that I love, but I wasn’t sure if their DMM options were anything worth looking into.

A teardown/review of a MM600:
http://budgetlightforum.com/node/58275

Dave did a "Mud Run" with a Klein MM500... it survived!

Mr. Scram · « **Reply #35 on:** July 13, 2018, 11:29:26 pm »

Quote from: GigaJoe on July 13, 2018, 03:29:39 pm

when I look at 257S, that what i don't like: AC voltage 60mV / 1000V ±(1.0%+5) @ 50-400Hz; 400Hz - really low , it more like electrician meter ...
seems only 860, 820 running to 20Khz .. 869 - to 100Khz

https://www.welectron.com/Brymen-BM867s-Multimeter_3 150 euro - consider , 5.5D ; precision, wide AC freq, bargraph, logging to PC, ...

A BM867S isn't a 5 1/2 digit model on AC. The BM257S has almost all of the features and advantages you mention for the BM867S. Much better than the cheap Chinese alternatives and barely worse than the more expensive competition.

Don't get me wrong, if you can afford a BM867S it's worthwhile, but a BM257S is a safe, good and more than capable alternative.

Deridex · « **Reply #36 on:** July 14, 2018, 05:57:41 am »

I think you can't do much wrong with the usual brands:
Brymen, Keysight, Fluke, Gossen etc.

At start i would prefer the Brymen because i think you get the most for your bucks.

Gizzygone · « **Reply #37 on:** July 18, 2018, 01:09:29 am »

I’m starting to lean towards a used Fluke 87. Any reason to not go with a 87iii or 87iv?

james_s · « **Reply #38 on:** July 18, 2018, 02:42:26 am »

Well, mostly the cost. I do like my Fluke 87, but I would only recommend it to someone with money to burn as a first DMM, unless they planned to be an electrician or something.

rsjsouza · « **Reply #39 on:** July 18, 2018, 03:02:06 am »

Quote from: Gizzygone on July 18, 2018, 01:09:29 am

I’m starting to lean towards a used Fluke 87. Any reason to not go with a 87iii or 87iv?

If you can get a 87III or 87V for a reasonable price, that's nothing wrong at all with them. The 87IV is a completely different meter - close to a Fluke 187.

Mr. Scram · « **Reply #40 on:** July 18, 2018, 05:27:33 pm »

Quote from: james_s on July 18, 2018, 02:42:26 am

Well, mostly the cost. I do like my Fluke 87, but I would only recommend it to someone with money to burn as a first DMM, unless they planned to be an electrician or something.

Same here. I do like my Fluke for its rugged simplicity, but if I had to pick a first multimeter on a budget I'd look at a BM257S, or BM869S on a slightly bigger budget.

Gizzygone · « **Reply #41 on:** July 18, 2018, 05:43:47 pm »

I ended up bidding on, and winning, an 87iii for just Under $100. The yellow over-mold looks a bit tattered, but the device itself looks to be in decent shape. I guess we’ll see how good it is when it shows up.

I guess the biggest question is if it’s caibrated well enough still!

james_s · « **Reply #42 on:** July 18, 2018, 07:51:47 pm »

I don't think I've ever seen a Fluke that had drifted out of calibration. A couple years ago I cleaned up a tattered old Fluke 29 a friend got and when I checked the calibration against my voltage standard it was bang on. Unless it has been damaged or molested I don't think that will be an issue.

Gizzygone · « **Reply #43 on:** July 18, 2018, 08:05:54 pm »

Any way to tell for sure without bringing it for calibration?

Maybe just try a fresh 9volt battery to test it against?

bitseeker · « **Reply #44 on:** July 18, 2018, 08:28:27 pm »

Well, it depends on your definition of "for sure." If that means to the accuracy stated in the multimeter's specifications, then you'd need appropriate references for voltage and current (AC and DC), resistance, etc. Check out the manual for all the types of measurements supported and their ranges.

A little less demanding might mean having some power supplies and components, the values of which are known (or can be measured with a known-good DMM), and seeing if the 87III displays roughly those known values. How rough depends on how many decimal places of accuracy meet your definition of "for sure."

Using a fresh 9-volt battery would tell you if the meter at least measures something around nine volts. The actual voltage is not known to a high degree of accuracy without measuring it. It may have been on a store shelf for a while or not long at all. Manually change to all the ranges that are high enough to accommodate the battery voltage and see if you still measure around nine volts. That will let you know that at least the DC volts functionality is OK for around nine volts. You'll still need some way to verify everything else that the DMM can do including the millivolts DC range.

JS · « **Reply #45 on:** July 19, 2018, 12:24:38 am »

You could get a new meter, even if cheap they come bang on from factory, like a $20 aneng AN8008 with 9999 counts which will be good to check and you end with a really nice meter for the lab, maybe even better than the 87 as the lowest ranges are sweet for electronics.

Some voltage regulators are pretty accurate, easily better than a 9V. You won't get a cheap way to compare to factory specs but much better than not knowing at all.

JS

Mr. Scram · « **Reply #46 on:** July 19, 2018, 01:42:44 am »

Quote from: Gizzygone on July 18, 2018, 08:05:54 pm

Any way to tell for sure without bringing it for calibration?

Maybe just try a fresh 9volt battery to test it against?

Get a cheap voltage reference from China or a more expensive one from elsewhere. You won't know the exact numbers, but they're accurate enough to at least a ensure it's within a handful of digits. That's plenty accurate for all but the most demanding stuff.

If you could measure your cheap reference on someone's calibrated meter you'll know quite accurately where you are.

A working 87III for under a hundred bucks is a nice score!

james_s · « **Reply #47 on:** July 19, 2018, 05:13:13 am »

Or find someone else with a known working meter to compare it with.

Really though, if you measure a few things and get reasonable values then the meter is very likely accurate. If something like a 10k resistor or 9V battery read wildly off then the meter is probably damaged in some way, but if it looks close then it's probably spot on. They just don't drift by any appreciable amount, you only need calibration if you need a paper trail for some sort of work where someone is auditing things.

drussell · « **Reply #48 on:** July 19, 2018, 05:21:29 am »

Quote from: Gizzygone on July 18, 2018, 08:05:54 pm

Any way to tell for sure without bringing it for calibration?

Maybe just try a fresh 9volt battery to test it against?

I would use a single alkaline cell like a single AA, C or D cell so there is less error instead of a bunch of series cells in the 9v battery.

Just like setting the bias on an old Dynaco tube amplifier...

GeoffreyF · « **Reply #49 on:** October 16, 2018, 08:29:19 pm »

I don't have a picture of the one I used, but this is a photo of it
Before that I had a Heatkit VTVM.


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Author Topic: First DMM? (Read 7661 times)

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