EEVBLOG #75 - Digital Multimeters

[EEVblog]

I honestly don't know what happened, I started talking, and the next thing I knew it was 52 minutes worth.
It was supposed to be a quick guide, really truly!

Flames invited!

Dave.

[Waifian]

  Nick likes this. 

[saturation]

I agree with 99.9% of what you said except in regards to bench desktop MM.  I think when it comes to accuracy and uV level [ likewise all V,I,R] measurements, they remain standards.  Few need to own one though, I don't.

If the "average" electronics person needs a meter with ~ 0.5% of rdg DC at $220 with many field useful features, why pay for .0004% such as a $9,000 Aligent 3458A ?





Note for bang for buck: 0.5/.0004 = 1,250 while 9,000/220 = 40.  That 1250x increase in accuracy for 40x the cost.

[migsantiago]

The bench dmm I have at school lab is awesome. It gives me 6 digits of precision, which I use to measure resistance on a high accuracy circuit I'm building. It also measures micro Volts, which was useful when I was testing some ultra low offset ampops. 

[allanw]

What do you think about getting used Flukes from ebay? I don't want to spend very much money and don't need super high accuracy. So, I was searching for the Fluke 83 and some of them have gone for $60-$70, which seems like a great deal:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=280491339945
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=270560542009

I guess the only concern is on features not working and having no recourse...

[EEVblog]

I agree with 99.9% of what you said except in regards to bench desktop MM.  I think when it comes to accuracy and uV level [ likewise all V,I,R] measurements, they remain standards.  Few need to own one though, I don't.

Exactly, and that's why it is not wroth recommending them to someone who watches a beginner video like this. I was of course referring to the low end bench meters, like for $200 you can get from various manufacturers and electronics shops. Uni-T are but one example. They have very few if any advantages over a hand held meter. If you need 0.0005% accuracy then you hardly need to watch my video!

If you want accuracy, get one of these babies, a bargain for the price:
http://instrumentation2000.com/gmcinstrumentsmetrahit30mtrms65digitmultimeter.aspx

Dave.

[EEVblog]

What do you think about getting used Flukes from ebay? I don't want to spend very much money and don't need super high accuracy. So, I was searching for the Fluke 83 and some of them have gone for $60-$70, which seems like a great deal:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=280491339945
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=270560542009

I guess the only concern is on features not working and having no recourse...

That's the chance you take to save some dollars, especially with the older original models. I've had mostly good luck with used Flukes on ebay though, but occasionally some bad apples.
I generally say go for it if you can't afford a new one, there are bargains to be had. The original Fluke 25 and 27 can be picked up pretty cheaply, and the 83 and 85 models generally go for less than the 87.

Dave.

[saturation]

I agree with 99.9% of what you said except in regards to bench desktop MM.  I think when it comes to accuracy and uV level [ likewise all V,I,R] measurements, they remain standards.  Few need to own one though, I don't.

Exactly, and that's why it is not wroth recommending them to someone who watches a beginner video like this. I was of course referring to the low end bench meters, like for $200 you can get from various manufacturers and electronics shops. Uni-T are but one example. They have very few if any advantages over a hand held meter. If you need 0.0005% accuracy then you hardly need to watch my video!

If you want accuracy, get one of these babies, a bargain for the price:
http://instrumentation2000.com/gmcinstrumentsmetrahit30mtrms65digitmultimeter.aspx

Dave.

I'm amazed!  Thanks Dave.  Its worth some study.

Your videos are not only factual, but fun and entertaining.  You made DMMs into a celebrity!

[saturation]

What do you think about getting used Flukes from ebay? I don't want to spend very much money and don't need super high accuracy. So, I was searching for the Fluke 83 and some of them have gone for $60-$70, which seems like a great deal:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=280491339945
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=270560542009

I guess the only concern is on features not working and having no recourse...

That's the chance you take to save some dollars, especially with the older original models. I've had mostly good luck with used Flukes on ebay though, but occasionally some bad apples.
I generally say go for it if you can't afford a new one, there are bargains to be had. The original Fluke 25 and 27 can be picked up pretty cheaply, and the 83 and 85 models generally go for less than the 87.

Dave.

I concur with Dave.  I've been shopping with eBay for sometime, but I have never paid more than I could afford to lose to fraud.  Some of those sellers linked seem pretty reputable, and they been vendors for some years, but its always a risk.  I remember when some of those working antiques were new    I'm impressed there is such an aftermarket for some of the older models of many brands.

http://cgi.ebay.com/Unbuilt-Sabtronics-Digital-Multimeter-DMM-Heathkit-doc_W0QQitemZ330416125135QQcmdZViewItemQQptZVintage_Electronics_R2?hash=item4cee55f4cf

Was my first DMM, the hand held version I built in 1980.  It used Intersil 7106 A/D, it became popular as a DMM on a chip, and is still made today

http://www.intersil.com/data/fn/fn3082.pdf

[dimlow]

Just one small comment.

I don't quite agree with the getting a latched continuity beeper. I like the scratchy ones as you call it, For testing micro switches and other switches they are great. You can tell by listening to the sound of a switch press if it has bad contacts. You get a nice clean sound with a good switch , but with a bad switch you can hear the intermittent scratchy sound. The latched ones only tell you if there is a connection or not. Not that useful really.

[Kiriakos-GR]

Well from my point of view, I did not found this video helpful .

I has hope , that would be a comparison , or presentation ... of mid range multimeter's ,
the ones that you can trust .

Comparing  6$  worth  with 400$ ones , even in just specs , become just confusing.

You had there  tree called cheapys .... the two was truly garbage , and the big one ,
was from the Taiwanese "  Pro's Kit "  , who builds multi meters , the last 20 years .
http://www.proskit.com/cgi-bin/proskit/aboutus.html

And you blasted  the instrument  at the " safety " area ... by keep talking for high power ..
And I am asking .. How high Dave ?  

How much High energy the home user, will find in his wall plug ?

My own "Pro's Kit" multimeter , since 1992 , it does have the 10Mohm impedance , it does have  2.6V continuity voltage,
frequency meter to 20kHz , internal temperature , capacitance tester,
plus transistor tester ... that you had call it as gimmick ..   why is an  gimmick ? , you had never  feel the need, to make an quick test, on a simple BC547 or 548 transistor .

By having the selector at the transistor tester , the multimeter should work as frequency meter to 20kHz,
test it ...  
 
The 1000V Dave , its not Industrial voltage , the max  industrial voltage are  3 phases 380V AC .

The 1000V on multi meters , was there to serve  the technicians who does Television repairs ,
that you have  1000V  with just 200mA  current ..

I work in the Greek Army ( small contract ) , and I am speaking all day with true electronic engineers,
and they complain ,  that even the FLUKE one gets damaged , from high voltage , even with out the fuses to get activated ... by just measuring voltage.
Thats why they prefer to use  mid range tools , because they cost less .

Safety ...  I love it , but as real electrician ,  I will never use my multimeter  at the main transformer who haves  25.000V .

All our factory, runs at the most of 380 AC Volts , 220 for ordinary lines ,  and 120V for some old American power tools .
  
And I have not found yet , any other electrician at the maintenance department, that we are as six ,
to complain about , the mid range multimeter .. that the Army provide to us .
And they are common models , mid range class.

VDE tests ?  exploding multi meters  ?  at what voltage they tested it ?

Dave, have you ever cause damage , in to a multimeter ?
Tell us , your own experience.

And one last matter , I noticed that the MetraWatt uses SIBA Fuses ,
that haves as  30.000A  breaking point ,   The Fluke use Fuses with just 20.000A  breaking point capacity.
So, write on the score board , Germany VS U.S.A.  1-0    

  
My own Fluke 87-5 , arrives tomorrow , I will respect it, as I do with all my other tools ,
but not more.




 

 

[Kiriakos-GR]

For testing micro switches ....... You can tell by listening to the sound of a switch press if it has bad contacts........ The latched ones only tell you if there is a connection or not. Not that useful really.

I agree with you , about testing micro switches by using this method, but not all multi meters , have the same buzzer - beeping sound .

The Fluke sounds like having an speaker in it, than a metallic buzzer .

At this point Dave's advice , about having more than one multimeter , are totally correct .
No just for measurement comparisons , but also for such specific tasks .

I am aware , that we have at list five deferent groups of people , looking for the "magic" multimeter that will satisfy all their needs ..

1) The amateur students , 2) The hard core hobbyists 3) The professional electricians 4) The developers of electronics  5) The professionals who repair electronics .

It would be wiser , if there was an separate video for its target group , one video for all groups  , causes mixed feelings and confusion.

Even so , we all need to thanks Dave , from the bottom of our hart ,  he did his best ..  
  

 

[saturation]

Maybe the title should be Newbies Guide to Buying DMM.  I think Dave was focusing his thoughts on newbies buying a DMM.  Experienced people like you would already know what you want!

But that could be another topic for a video.

Exploding DMM are rare because most work environments, at least in the USA, won't allow such incompetence in the worksite.  In the USA, such problems will create major lawsuits.  We spend a lot of time in safety training where such a risk exits.  However, problems have been reported by some consumers/users.

http://gossenmetrawatt.com/english/seiten/cautiondangerousmultimeters.htm

Fluke has even recalled test leads because of supposed problems.

http://www.cpsc.gov/cpscpub/prerel/prhtml04/04131.html

A home user can find high energy risks if they work in category III risk areas, that is working near the junction box, or on 220V appliances like if they try to troubleshoot their washer/dryers.  High voltages spikes could be caused by EMF from the motors particularly if the user tests by turning the units on and off.  

I agree, hFE can be helpful if you work with a lot of transistors.  But that is an out-of-circuit test.  For that it might be easier to buy a cheapie MM as a transistor tester.  After all, you can't have just one DMM     In Germany, testing by their product safety group found that the hFE socket is a risk for high voltage injury since it shares a common ground and, you can connect a transistor to it and still use the DMM for voltage measurements.  They ran required safety tests on 105 store bought "consumer" grade DMM. All failed.  Its consumer because in Germany, products used by professionals must pass safety regulations.  In the US, all professionally used DMM are certified for safety regulation, but its use is not mandated by law.  However, if someone is injured because of non-compliance with safety standards, the US labor office, OSHA, will hold the employer and work place liable and sue them for fines or jail time.

http://gps.sozialnetz.de/go/id/pn/

[ In German, but translation available via google]

Some models are sold all over the world, with different brand names:





Fuse ratings won't matter so long as both DMM conform to the safety standard.  That's all we care about.  If that's what the manufacturer mandates in their DMM, that's what we should use.  Note the CE safety mark on the lower right, that is useless, it can be made by the manufacturer to suggest their internal testing meets IEC specs, but not that tested by independent testing.

In the Navy work, I'm not sure why your engineers lost so many Flukes, but in the US we would return those units.  All the top end Flukes are guaranteed for 'life'.   It sounds like they experienced high voltage low current transients that likely arc'd inside the casing, suggesting those Fluke's are either a very old design or defective.

http://www.cpsc.gov/cpscpub/prerel/prhtml02/02231.html
 
In the USA, if a Fluke is reported to act strange, it will trigger them to investigate even recall items like test leads.  How much more to be damaged while being used as designed?

[EEVblog]

Maybe the title should be Newbies Guide to Buying DMM.  I think Dave was focusing his thoughts on newbies buying a DMM.  Experienced people like you would already know what you want!

I did originally have newbie in the title but decided to remove it, because I figured there might be some useful info in there for people who don't consider themselves newbies, so may not have viewed the video otherwise.
That raises an interesting point actually, I've learned that the titles of my videos are very important. Regulars will of course watch every video, but attracting new viewers when they search youtube or google is another art entirely.

That meter is frigg'n hilarious!

Dave.

[mausball]

Great vlog! My only beef (and the one that finally got me to register) was the rag on bench DMMs. Handhelds are wonderful, and even the $1200 GMC 6.5 digit handheld is nice, but if I want fast, reliable, 4 wire high precision measurements or simultaneous voltage and frequency numbers from a set of probes, it's hard to get that in a package better than a nice bench meter. Oh, and no batteries to lose, bigger, brighter displays, proper data capture, proper GPIB or serial connections, etc. I have a pile of handheld meters, and I love them dearly, but I also have a few bench meters (including a phenomenally nice 7.5 digit Agilent I got for a price I still don't believe), and I use them quite a lot.

I suppose it has a lot to do with one's personal work style, or how one learned the craft, but I think out-of-hand dismissal of bench meters is just a little....rantish. But that said, keep on ranting! I love the blog!

[MightyTwin]

*snip*

http://gps.sozialnetz.de/go/id/pn/

[ In German, but translation available via google]

*Snip*

http://gps.sozialnetz.de/global/show_document.asp?id=aaaaaaaaaaaakar

This 'meter looks vaguely familiar...

-MightyTwin.

[EEVblog]

I suppose it has a lot to do with one's personal work style, or how one learned the craft, but I think out-of-hand dismissal of bench meters is just a little....rantish. But that said, keep on ranting! I love the blog!

The blog was aimed at beginners, so therefore all the positives about high priced high end bench meters aren't really relevant to that audience.

Dave.

[Waifian]

Check out what they are making us use where I work. Note the CAT labels....
I dropped this from 3 feet and it turned into a maraca. 

[Kiriakos-GR]

For the moment I will just post a picture , so to share my enthusiasm , with the few who could understand  my feelings .. 

Arrived today ... Just picked it up , after my morning job .
So I am a dead body , and hungry one , with out energy to do any tests ..
Other than just an AC measurement .. 



More news, later on ...   
It came all the way from Honolulu to Greece with express shipping 43$..
Damn Shinny , all fuses good , back light ok, not sign of use !! or even a small one     

[saturation]

I forgot to mention the CAT II rating on the left of that image.  Like many cheapos, how do you know its really CAT II?

Notice the setting on the selector knob: 200V, 200KOhm, and mA in one setting.  With the V-Ohm-A setting a slide switch, you can go from measuring volts to short circuit with one switch.

I used this DMM as example because I've also seen it, its very small, shirt pocket sized.  It measures DC circuits OK, but how will its target market, the consumer, know not to use it for more?

On the German pdf file, you will see a link to RAPEX:

http://ec.europa.eu/consumers/dyna/rapex/rapex_archives_en.cfm

Unlike the US, EU is willing to recall or ban some multimeters under consumer product safety rules.

Another idea for Dave is doing stress tests on these elcheapo DMM and see how they survive where a professional meter is preferred.  

Note, in the German pdf report, the MM on the right of the picture is very much like a portable Fluke scope, so its monitoring the same conditions/load as the test DMM.

Maybe the title should be Newbies Guide to Buying DMM.  I think Dave was focusing his thoughts on newbies buying a DMM.  Experienced people like you would already know what you want!

I did originally have newbie in the title but decided to remove it, because I figured there might be some useful info in there for people who don't consider themselves newbies, so may not have viewed the video otherwise.
That raises an interesting point actually, I've learned that the titles of my videos are very important. Regulars will of course watch every video, but attracting new viewers when they search youtube or google is another art entirely.

That meter is frigg'n hilarious!

Dave.

[saturation]

I'm happy for you, K.  Give us your review as you have time.  It looks in very good shape, practically new.
You're old DMM seems to be quite well used, a testament also to its durability.

Note, for safety the lightning annunciator to warn you about the shock potential of the V you have on.

For the moment I will just post a picture , so to share my enthusiasm , with the few who could understand  my feelings ..  

Arrived today ... Just picked it up , after my morning job .
So I am a dead body , and hungry one , with out energy to do any tests ..
Other than just an AC measurement ..  

[mausball]

The blog was aimed at beginners, so therefore all the positives about high priced high end bench meters aren't really relevant to that audience.

No worries Dave, I know it was. I guess my kneejerk post was related to the fact that there are lots of professionals who watch as well.

Check out what they are making us use where I work. Note the CAT labels....
I dropped this from 3 feet and it turned into a maraca. 

Ouch! My WaveTek 27xt (from back in the blue-box pre-MeterMan takeover days) is still going strong. Off a ladder, off the roof, off a moving train (!), and knocked off countless benches over the years. I guess they don't make them like they used to....

[Waifian]

@ Kiriakos-GR
I didn't know they made those in black, thats pretty sweet!

[Kiriakos-GR]

@ Kiriakos-GR
I didn't know they made those in black, thats pretty sweet!

All  87-V ( 87-5) has this gray dark color .

With the Yellow protective holster around it , looks like a "half peeled" banana .. 

[Waifian]

Maybe the picture is making it look Black. I can't seem to find any pictures using a google picture search that shows one as dark as yours which looks solid black to me . That's still an awesome meter. I have a 189(personal use), all the bells and whistles non of the battery life.  

The Fluke 189 has only about 74 hours of battery life where the Fluke 87 has about 450. I guess it doesn't matter too much because I only use it when I am working on things at home and usually turn it off after making the measurements I want. One of these days when I can afford it I may get a 87.

I am broke for now though because of my fairly recent Rigol purchase.  

Edit: Never mind I found some that look the same.