I Want to Buy a Multimeter...need advice

[photon1k]

I'm finding this to be an on-going struggle. Like others I have owned several cheep-cheep metres over the years. I dithered and delayed getting a "decent" one for years because I was too lazy to look at and compare all the specs. I eventually bought a ~60$ chinese Uni-T - and guess what? I'm still finding out about weaknesses it has.

I just learned about something called burden voltage and how it can affect DC current measurments in low voltage circuits - something we do a lot of. I never saw a burden voltage specification in any of the metre specs listed on line. But there it is, rearing up to bite me after I bought the metre.

Lesson learned: Comparing specs isn't enough. I need to understand more about the specific measurements I wish to perform before I can make an informed decision when buying a metre.

[HKJ]

@photon1k

I just learned about something called burden voltage and how it can affect DC current measurments in low voltage circuits - something we do a lot of. I never saw a burden voltage specification in any of the metre specs listed on line. But there it is, rearing up to bite me after I bought the metre.

If the DMM has a decent milli volt range, it is very easy to get around, get a couple of small resistors and use them as current shunt, then measure the voltage across them. This way you will often get a lower burden voltage, than even a good DMM.

Using resistors like 0.01ohm, 0.1ohm and 1ohm makes the math easy.

[Don]

@Chloe

@Don

I don’t actually know how easy or otherwise it would be to recalibrate them. It’s probably pretty straightforward unless you want to measure large currents all the time - but HKJ has tips for that. If sixty545 is around, he used to design electronic test gear so would also be worth listening to.

Thanks, Don. I am going to start scouring Ebay. I don’t really need the high resolution but I do want something that will last, without having to fork out to maintain it.

If it says anything about dodgy display, it's probably best to avoid. They do die - Fluke don't make the displays.

Round here, they want about 8x what I paid for the meter to calibrate it and replace the display.

Here's how to get one into calibration mode.

What Does Infinity Mean on an Ohmmeter?

Fluke Repair | Fluke Meters | Fluke calibration

[Ouchyfoot]

I’m kinda leaning toward the Brymen BM-257. It seems like a pretty solid mid priced DMM. It is also sold in th e US as the Greenlee DM-510A.

The only thing that’s making me think twice is the 8A fusing instead of the usual 10A. Is that really anything of a big concern to me as a flashlight hobbiest. It’s not like I’m Scaru or anything. Someone from Mouser took one apart and said it has the same 10A fuse inside that is common to most 10A DMMs.

Here is The PDF for the 250 series. I’m looking at the BM-257.

[Chloe]

It looks very familiar somehow, so I am wondering about the OEM and the possibility of getting it cheaper still from a Chinese supplier. But it’s really late here. How mid-priced are they? I saw the Greenlee for something like $140 on Amazon!

At a glance it looks like a nice meter. Has high current, temperature, resistance and continuity beep. Range button I assume bypasses auto-ranging. Is it backlit too? If so I hope you can turn it off as this is a battery killer.

Anyway, if you have a gut feeling about this one, I’d listen to that.

[Ouchyfoot]

Brymen are made in Taiwan, and are sometimes rebranded under various names. I think I’m gonna go for it. I guess I’ll pick up some extra leads and plugs for it while I’m in the shopping mood. Amazon.ca is out of stock of the Greenlees. This guy is a little cheaper out of Hong Kong, not a lot, but some.

[ILIKEFLASHLIGHTS]

The one I posted is probably one of the most popular multimeters you can buy for $25 shipped to your door.

[PilotPTK]

There are tons of ‘good’ low priced meters… I just can’t imagine spending $100+ on a meter from anyone other than Fluke, Agilent or Hioki though…

It does look like a nice meter, but it just doesn’t have the field-provenness of the Flukes, Agilents and Hiokis. If you’re going to save money on a lesser brand, why not save a lot of money and buy one of the well-reviewed $25 - $50 meters?

It’s your money, so obviously buy what you’re comfortable with.

PPtk

[ILIKEFLASHLIGHTS]

Well I guess it all depends on what your wanting in a multimeter. It’s like a Corvette and a Escort deal to me The Corvette may look better and get you there faster, but the Escort will do the same thing for way less money.

Now if your an electrician and need the Fluke, I say go for it. But for my purpose and what I use one for the Equus 3320 is all I need.

[Ouchyfoot]

Can you put rechargeable cells like Eneloop in these multimeters, or do they need 1.5v?

[PilotPTK]

@ILIKEFLASHLIGHTS

Well I guess it all depends on what your wanting in a multimeter. It’s like a Corvette and a Escort deal to me The Corvette may look better and get you there faster, but the Escort will do the same thing for way less money.

Now if your an electrician and need the Fluke, I say go for it. But for my purpose and what I use one for the Equus 3320 is all I need.

That’s exactly my point, but you sure wouldn’t pay the $60,000 corvette price for the escort…

PPtk

[PilotPTK]

@Ouchyfoot

Can you put rechargeable cells like Eneloop in these multimeters, or do they need 1.5v?

Most, Yes. Some, No. Depends how picky they are. Some will only work on greater than 1.2 or 1.3V, others work fine down to .7 or .8… You’ll have to do some research on the particular model. Dave at EVBlog always checks that in his reviews…

PPtk

[Ouchyfoot]

How would the meter react if it didnt like 1.2v?

[PilotPTK]

Might just not turn on, or worse, might give completely inaccurate readings. I’ve seen meters that do both. Reading “Negative” resistance is a common ‘feature’ on low-quality meters with low batteries…

[ryansoh3]

Yup, my cheapie was reading almost double the voltage and I was getting really confused.

Luckily it had a battery warning symbol and figured out it was the battery, and it was.

[Foy]

I don't know man . . . after watching this guy http://www.youtube.com/watch?v=gh1n_ELmpFI Foy is putting down forever the Jeopardy paperback: DMM Roulette for 6,000 and the Counts That Haunt Me.

dailydoubleFoy

[photon1k]

@HKJ

@photon1k

I just learned about something called burden voltage and how it can affect DC current measurments in low voltage circuits - something we do a lot of. I never saw a burden voltage specification in any of the metre specs listed on line. But there it is, rearing up to bite me after I bought the metre.

If the DMM has a decent milli volt range, it is very easy to get around, get a couple of small resistors and use them as current shunt, then measure the voltage across them. This way you will often get a lower burden voltage, than even a good DMM.

Using resistors like 0.01ohm, 0.1ohm and 1ohm makes the math easy.

Thanks for this. I went to your site and found the tutorial - in fact I recall having seen it some time ago but did not understand the need for it then.