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  • EEVblog #75 – Digital Multimeter Buying Guide

    Posted on April 14th, 2010 EEVblog 52 comments

    Who else in the industry can give you 52 solid minutes of beginner advice on buying a multimeter?
    Dave of course!, who started out wanting to give some “quick” advice, but as usual Dave likes to rant…
    So you get a feature-by-feature breakdown on what makes a good digital multimeter. It turns out there is a surprising amount of stuff to talk about on the humble multimeter.

    The other video on meter counts & accuracy:
    http://www.youtube.com/watch?v=U4JFeU-o2kc

    And this is what happens to cheap meters when you overload them:
    http://gossenmetrawatt.com/english/seiten/cautiondangerousmultimeters.htm


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    • http://www.soasystem.com shafri

      i’m the first commenter here haha! i should get a prize…
      erhmm. sorry. nice topic though

    • Brian Hoskins

      Hi Dave, good blog.

      I have to agree that battery life should be a major consideration for your *main* everyday meter. This is because there’s nothing worse than having your train of thought interrupted when you’re at the lab working on a piece of hardware or troubleshooting a problem.

      Often managers and other non-technical staff will really annoy me with this, they come up and ask me stupid questions, or ask me to do some silly thing that could have waited until later, and then they’ve interrupted my entire train of thought about what I was doing, and that’s really annoying.

      With a multimeter it’s the same thing. Guaranteed that unless your meter has a decent battery life, every time you’re just getting into some depth with what you’re doing the damned battery warning indication will come on and then you’ve got to go hunting around for new batteries and by the time you get back to your bench you’ve lost your train of thought. Really annoying.

      So don’t buy a meter with crap battery life unless it’s not going to be your main meter! Agreed!

      Brian

    • http://garyc.isa-geek.net Gary C

      here is my cheapy multimeter: http://www.flickr.com/photos/49352615@N08/sets/72157623728529753/

      i’m just a hobyist, i used that dam thing for two years before i got the courage to see it’s insides knowing just how bad it could be :)

      i have since replaced it with a second-hand fluke.

    • George Graves

      Hi, I’m posing in the comments.

      Hi, I’m posing in the comments.

      (just messing with you Dave – we love you!)

    • Andrew S

      Dave, how many multimeters do you actually own? :-)

    • Al

      My multimeter has a transistor tester which, as a newbie, I find quite useful. I’ve blown a few transistors while playing with circuits and found a transitor tester handy to know if the transistor is OK (I dont care about specific values, just does it work.)

      Looking forward to some “mythbusters” style testing of multimeter’s….. KBOOOOMMMMMM

      • http://www.soasystem.com shafri

        200% agreed with the transistor tester (incl capacitance tester)

    • Karl

      Need a transistor tester? Build your own with a couple of parts (maybe worth 10 Euro)

      http://viewvc.coremelt.net/viewvc/avr/semiconductor_tester/?view=tar

      And you get not only an NPN and PNP transistor tester, but it doubles as an MOSFET (N, E, enhancement, depletion) JFET (N, P), thyristor, triac, double diode (CA, CC), parallel and antiparallel, series and normal diode tester.

      And it has a rough resistor and capacitance measurement range, too.

      What you don’t get is input protection :-)

      The software supports five languages, German, English, Polish, Czech, and Slovakian.

    • Prad

      For the 123MB of ABC of multimeters, the nerds and geeks salutes you.

    • James

      Excellent distillation of all your multimeter advice Dave.

      Would you consider doing something similar for LCR meters?

    • Prad

      Hi Dave,

      My appreciations have fallen short to praise your work. I own a Fluke 115 and have recently won a Fluke 233 on the Imagine the Possibilities contest. I intend to share my impressions of judging these products by your law.

      1. The thing that is seriously missing is the mention of the Bar Graph feature. Keeping the lengths and breaths of the Bar Graph feature aside, it is a necessity in every one in ten debugging application. I regret the Fluke 233 could not manage it.

      2. For an illustrated lesson on safety, put a link to the video on the Gossen Metrawatt website displaying a multimeter go up in flames and burst like a firecracker.

      3. The Fluke 115 and the Fluke 233 does not go at par with the accuracy formula. They feature 6000 counts with 0.5% and 0.25% basic DC volts accuracy respectively. Abiding by the formula, Fluke does not know what they are doing.

      4. Another thing that was worth mention is the Crest Factor for True RMS. The Fluke 115 and the Fluke 233 feature a Crest Factor of <=3 at 4000 counts decreasing linearly to 1.5 at full scale. As a rule of thumb, the meter should be up ranged manually beyond 4000 counts to utilize the True RMS feature, which is extremely impractical.

      5. And for God

    • http://www.vssec.vic.edu.au/ Shaun Clarke

      Dave, do you have any idea what voltage and current the meter was overloaded with in the Gossen Metrawatt video? Or what mode it was in to cause such a fireworks display?

      • http://www.eevblog.com EEVblog

        No, don’t know for sure, sorry. I’ve been meaning to ask Gossen about that for a while now.
        I believe the standard VDE et.al type test is in the order of 8KV spikes.

        • http://www.vssec.vic.edu.au/ Shaun Clarke

          Good, so I shouldn’t expect my meter to explode quite so spectacularly if it comes into contact with a mains AC short :).

          • Karl

            Wrong. You forgot about surges, and they go into the kV range on mains AC. And that’s why e.g. 600V CAT II (a typical specification junk multimeter manufacturers pull out of their ass for meters sold in 240V areas) requires a meter to withstand 4 kV transients.

            Only that those $5 junk doesn’t withstand such a surge. And their probes don’t. And you won’t.

            • Shaun Clarke

              Interesting.

              Can someone (or yourself) elaborate on these surges?

              Are they a somewhat regular occurrence or do they only happen during a fault condition?

              What specifications exactly define if a meter will withstand such surges? I’m guessing this is linked to the CAT ratings?

    • brims

      Nice video, high quality information as usual. Speaking of dangerous meters, Gossen has a nice video about them. http://www.gossenmetrawatt.com/english/seiten/cautiondangerousmultimeters.htm

    • Phil H

      Dave, you have a bit of a sig fig problem…0.5% is 1 part in 200, so with a 3-1/2 digit meter, you can be off by 10 in the least significant digit.

      For analogue purposes, you really need 0.1% or better accuracy.

      Cheers

      Phil Hobbs

      • http://www.eevblog.com EEVblog

        @Phil
        Yes, that’s what I was trying to imply, that the least significant figure can change by 10, that’s how most meters are speced vs their count.
        Looking back that wasn’t really clear in the video, and kinda confusing. I can see how people would get the impression I meant +/-1LSD instead. I should have explained the last digit is essentially meaningless.
        Dave.

    • Jay

      Thanks for the video, Dave. Lots of good info. I think you were a little too hard on the cheap meters. They have their place. I taped a cheap $7 meter to my motorcycle fairing to measure stator output at various rpms. If it falls off it won’t break my heart. I’m continually grateful for utility in other situations where the Fluke is too dear to risk.

    • http://msjaye.com MsJaye

      An excellent episode, thanks. Perhaps a good followup might be to present decent choices for a meter at say $50, $100 and $200?

      • http://www.eevblog.com EEVblog

        @MsJaye
        I’m already trying to organise a multimeter shootout for meters in the $50 and $100 price categories, I hope it comes through.

        • http://www.test-equipment-shop.com.au Duncan Livingston

          For the benefit of your US followers I have head good things about the Sear “homebrand” craftsman multimeters. Sears deliver to Australia free if you order online – perhaps there is already a USA fan out there that works at Sears that could help out?

          Duncan

          • http://www.eevblog.com EEVblog

            For the benefit of your US followers I have head good things about the Sear

    • http://www.test-equipment-shop.com.au Duncan Livingston

      Wow Dave

      I wouldn’t be surprised if if there are trade college teachers around the world smiling and thinking “that is an hour lecture I can get out of by clicking play”.

      A word of warning anybody looking at eBay and seeing the Fluke 15B or Fluke 17B.
      These are meters designed for Asian markets – they DON’T have the same safety ratings or accuracy ratings as the the meters Fluke market to the rest of the world. What Dave was saying about CAT ratings should be noted. Here in Australia mains voltage can commonly be 230V +10% or -15% and be within what our power suppliers consider normal and acceptable. Using a Fluke 15B or Fluke 17B which has a CAT III 300V rating you are already dangerously close to that maximum. People, if you plan to use the multimeter for electrical work buy a Fluke 115 or Fluke 117 as a minimum or my new favourite after seeing Dave’s review the Fluke 28 II.

      • Shaun Clarke

        Duncan,

        Isn’t the nominal voltage in Australia 240 volts not 230 volts?

        Also don’t forget that if you are doing any work with larger switchboards, or any 3 phase wiring or appliances, 415 volts between phases is WELL over the 300 volt limit also.

        Shaun Clarke

        • http://www.eevblog.com EEVblog

          Isn

          • Shaun Clarke

            Good to know :-).

            I havn’t seen 230 volts anywhere yet. My workplace is actually about 245 volts at times.

    • Mike

      Digi-Key sells TPI, and they have a nice range of meters that cover low to high ends. I like the value of their 183 model.
      http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=290-1183-ND

      If you click on the selection guide in the datasheet section, they have a nice side by side comparison of their product and specs.

      Thanks for the info Dave.

      Mike

    • peet

      hey dave,

      whats this board in your intro to each episode?

      looks really interesting!! i was able to identify an fpga und gigabit ethernet.

      what is this supposed to do?

      would be great if you could explain this to us in future episode of your great video blog :)

      regards

    • Shaun Clarke

      peet,

      Dave gave a brief introduction to this board when the intro was fist introduced.

      You can find that here:

      http://www.eevblog.com/2009/09/19/eevblog-32-tandy-1000-retro-computer-time/

      Hope that helps.

      Cheers,

      Shaun

    • Shaun Clarke

      peet,

      Dave gave a brief introduction to this board when the intro was fist introduced.

      You can find that here:

      http://www.eevblog.com/2009/09/19/eevblog-32-tandy-1000-retro-computer-time/

      Hope that helps.

      Cheers,

      Shaun Clarke

    • alm

      I disagree that bench meters aren’t useful for everyday use, and I think that industrial safety ratings for hobby electronics are a bit overkill.

      Note that I do like Fluke handhelds, I own two of them and consider most others that I’ve seen garbage (I’ve never seen a Gossen or Agilent in real life).

      Bench meters are (almost) always mains powered, which means that I can leave them on for hours without them powering down because I didn’t hit a key for ten minutes, or worrying about running down the batteries if I leave them on all night.

      Because they have power to spare, their displays are usually much better, often VFD or LED. I like the Keithley 199 in this regard: a 14/16-segment LED display that can be read from far away and from any angle. And it probably costs less used than a used high-end Fluke (I paid less than $100 including shipping).

      Because many were (also) designed to be used in a system, they’re usually much quicker than a handheld. A good handheld will do 4 readings per second, I think the Keithley 199 can do 60 in 4.5 digit mode, and more recent ones are even faster. This means a noticeably faster response.

      The controls are nicer for bench use: push buttons instead of a rotary switch (less likely to shift the meter during mode change), proper range up/down/auto buttons instead of pressing the range button over and over.

      They are much larger than handhelds, but they can be properly stacked with other test equipment, so they don’t take much extra bench space. They’re also less likely to be pulled over by the test leads.

      The disadvantage is that they have less ‘gimmicks’ like capacitance and diode test. I use an LC meter for capacitors (wouldn’t trust my Fluke for anything smaller than power supply bypass caps, and mainly care about ESR for electrolytics), and use my Fluke handheld if I want to measure diodes or temperature.

      About the safety ratings. Most of the stuff I measure is low-voltage behind a power supply, so CAT I 50V would actually suffice. Occasionally I might be working on a power supply, which would be CAT II 250V (I’m not within a few meters or so of a CAT III connection). Most hobbyists are probably similar. Even seems to Agilent agree: the Agilent 34410A (current standard bench meter in the industry) is Cat II 300V/Cat I 1000V. It also uses a simple glass 3A fuse. Apparently Agilent thinks this is enough for electronics bench use.

      Those glass fuses are designed for 250V mains use (which is why you often see them at the primary side of a power supply), so it should have no problem interrupting a short between two mains lines (CAT II).

      Cat III and Cat IV are rarely encountered in home environments, and are mainly targeted at industrial electronics or electricians. Which is why something like the Fluke 80-series has a Cat IV rating.

      I’m not advocating the use of cheap fake-CAT rated meters, and of course extra safety never hurts, but I don’t think that applying industrial safety specifications to a hobby electronics bench makes sense. How many people take the other safety precautions (protective clothing, a face shield, using tested gloves when working on live equipment) for their blinking LED?

    • John W.

      Kinda wish there were multimeters with built-in ESR meters. That’d be nice.

    • http://maggidev.com Ben

      The cheappy multimeter actually managed say im out of range for about 1ms before it died.

    • Ray Jones

      One Hung Low Brand

      Love it!

      • http://www.eevblog.com EEVblog

        One Hung Low Brand

        Love it!

        A lot of people don’t get that one!

        Dave.

    • Bleyfuss

      Cheap ones: sometimes useful to have around in handfuls, to cover multiple DC test points… mine usually die of the manual selection switch wearing out, literally losing its balls….

      Usability: OFF on the main selector switch accelerates that problem, and is extremely inconvenient (as well as probably actually dangerous) if you want to power off anything you want to keep wired into a live bench experiment (how do some of the autorangers deal with that anyway?!)…

      Bench meters: not that useless, and I wonder you did not mention the used market possibilities there… recently got myself an old Racal/Dana, well aged so the cal won’t shift a lot anymore, with 160000 counts, 4 terminal ohms, very fast update, and near electrometer grade input resistance for not more than what a medium quality hand meter would have cost me new…. and the clicking autorange relays make a very good and fast acoustic continuity tester actually.

      Trimpots: at least you can realign the b****r without being dependent on obscure software….

      Leads: I like using very thin,long (pulled from old printer cable) twisted pair with micrograbbers as a test lead… I hate heavy and springy test leads.. of course this is NOT what you want for straight mains connected heavy machinery, vacuum tubes and car batteries :)

      Transistor tester: better than nothing if you do not own a dedicated hfe meter or curve tracer…

      Clamp meters: no mention? The ones that do DC and resolve to 10 or 100 mA are nice for quick current consumption checking if your PSUs do not provide current meters.

      As I said, that’s all my opinion as a hobbyist mostly dealing with electronics lab work, not maintaining appliances and high voltage equipment..
      I wonder why you always put so much weight on safety and ruggedness features mostly interesting for the industrial tech and electrician in the field?

      • http://www.eevblog.com EEVblog

        I wonder why you always put so much weight on safety

        Because I want the newbies to understand and be appreciative of the various potential dangers of measurement and possible inadequate meter design. And I think (sometimes) over-engineered meters make good positive design examples.

        Dave.

    • http://www.technojunk.nl Niels Kloppenburg

      Folks,
      There is a low – budget fluke meter on the market only for Asia, the fluke 17B.
      Is this something people recommend to me?

      Mayby something to review some time?

      Niels

      • peet

        i’m about to buy this meter.

        dave can say “go” or “no” ? for me as an beginner, it seems to be a nice device.

    • Ryan Leach

      thanks dave, altho it is a bit of a information overflow i think i might need to watch this again some time.

    • Radoslav

      Hi!

      Thanks for the extremely informative guide! I recently bought this multimeter: http://www.velleman.eu/distributor/products/view/?id=377440

      From what I’ve understood from the video, it should be a fairly good general purpose multimeter. But is it actually?

    • Bernhard Weller

      Wow, so this got me quite curious about my own multimeter I bought a few years ago without actually having any idea on what a good meter is made of.

      It’s a Peaktech 3340 DMM.
      So following your lead, I took it apart. Well it costs around 36

    • tzangcr

      Excellent Guide.

      Would you do one for purchasing an Oscilloscope as well, please? I took a cursory glance at your Episodes list, and nothing jumped out at me as an oscilloscope-parallel.

      Thanks.

    • softman

      I am not sure why you say the transistor hfe meter is useless. Can you please explain this.

      • http://www.eevblog.com EEVblog

        Back in the days when transistors were expensive and used in more designs, you’d salvage them and reuse them, test them etc, and a HFE transistor tester might have been useful to a hobbyist.
        But these days the cost is nothing, so why not use a brand new fully speced transistor? in which case you don’t need a HFE tester unless you have a very specific need.
        It is also the reason why few if any professional multimeters ever had or have now a HFE transistor tester.
        As always, YMMV.

        • Phil Reynolds

          If I need to test a transistor, I get a sufficient result using the diode test mode and a 10k resistor. If I actually need a more elaborate test, there’s a fairly simple circuit that can be breadboarded in no time, using only two resistors, a 9V power source and a meter set for milliamps.

          My tests are fine for go/no-go purposes which are all I need. The only transistors I usually need to test are the ones that work towards producing the various power rails in the “antique” computers I sometimes handle.

    • Kirk

      Hey Dave
      Can you please do a review on the fluke 787 process multimeter.
      Thank you.

    • Patrick

      Based on the info in this video I just bought an Extech EX430 for $58 hobby meter.

      http://www.extech.com/instruments/product.asp?catid=48&prodid=272

      Thanks Dave!