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  • EEVblog #26 – Multimeter Counts, Accuracy, Resolution & Calibration

    Posted on August 21st, 2009 EEVblog 23 comments

    All about Multimeter display counts, accuracy, and calibration.

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    • Brian Hoskins

      I have to admit that even as an Engineer working in the trade, I have often found myself confused with this accuracy / count business. Also, having questioned colleagues on it, I have found that the confusion is quite wide spread. So it’s not only newcomers to the industry that can find themselves uncertain about exactly what it means!

      Very good blog this one :)

      On a slightly different note, I have to say that whilst I do share your passion for Fluke multimeter instruments and also HP bench multimeter instruments, I do not share your approval for the Meterman stuff. The meter itself is quite good but we bought a load of these for our company staff a couple of years ago and I’ve found that a lot of them share a common problem with resistance measurements. Often they don’t read accurately when measuring <100 Ohms, which seems to have something to do with the actual measurement selection switch because sometimes if you press down on it the problem can be temporarily cured. Not all of the meters do it, but quite a few have developed the problem over time so it seems to be a poor quality aspect of the meter. Also I find the continuity beeper to be too quiet, which is frustrating in general use – especially if you find yourself having to buzz something out on a factory shop floor or something like that.

      Keep up the good blogs!

      Brian

      • http://www.alternatezone.com/eevblog admin

        Thanks for the heads-up on the Meterman. Guess I haven’t had mine long enough to encounter any issues. The range switch is always the biggest problem with meters of all types. Not so top-quality gold playing on the contacts in the case of the Meterman perhaps?
        I still don’t like how the base model Flukes use the range switch for ON/OFF that’s just extra wear’n’tear on the range switch.

    • Matt McCartney

      Hey Mr. Jones, I’ll be waiting to hear about power supplies and function generators :)

    • http://www.mastrogippo.it Mastro Gippo

      Damn, I must stop wieving your videos… You made me buy the Rigol oscope, now I find myself browsing ebay for a new multimeter… And I already own a Fluke 73!!! :) Well, I actually was already on the market for a cheap oscope, but I couldn’t convince myself to get a crappy OWON… My friend got one, and it’s a relly poor choice! I’m glad I found your review before purchasing one.

      Oh.. Nice shirt! It’s my motto too! :)

    • Kathy Quinlan

      I quite like the fluke meters, I started of in 1990 with a Fluke 77, then bout the Fluke 29 (a 79 meter in safety yellow (helps to find it on the bench when working on something that is opened up (like an industrial UPS)))

      I have a ISOtech meter in my install kit, basic thing with no large current scale (ie only measures upto 300mA IIRC)

      I have never had a hand held meter better than a Fluke. Would be interested in others opinions on the other brands :)

      Kat.

    • http://www.davidaa.co.uk David

      Hi David,
      I thought I’d just commend you on your excellent blogs! I have picked up many great tips and hope to learn many more.

      As a final year electronics undergraduate, I would love to have more of an insight into the day-to-day activities of an electronics engineer in industry. It would be interesting to see whether my idea of what happens is much different to what actually does. I hope you potentially consider this for a future blog!

      Dave

    • Kathy Quinlan

      Mastro, I have put the rigol on my Christmas list ;)

      Kat.

      • http://www.alternatezone.com/eevblog admin

        You can now get the Rigol for around AU$480 *delivered* from sellers on Ebay! Insanely low price.

    • Andrew

      Kathy, don’t dismiss the new GW Instek GDS-1000A series. Instek beefed up the older GDS-1000 series.

    • http://www.mastrogippo.it Mastro Gippo

      David, one last question before I click the “Buy it now” button.. Since the 100MHz and the 50MHz models of the Rigol scope have very little differences, and I see that you are able to measure the static charge at 100MHz with your Rigol, do you think it’s worth the extra money to get the 100MHz version? It’s almost double price.. I don’t know what I will need in future, so I’m thinking in a “better-to-be-safe-than-sorry” way.
      Thank you

    • ewertz

      My advice to David-final-year-electronics-undergraduate would be to start reading the complete works of Dilbert, paying particular attention to the trials and tribulations of Ashok.

    • Kathy Quinlan

      I used to have a nice push button clamp meter (used to as the shed in a place we were renting leaked and it was in a plastic create and it was submerged)

      It seemed reasonably accurate on low ohms (which surprised me, I only bought it as an ac clamp meter to measure current draw when doing stage lighting (HRC fuse links are EXPENSIVE) and hard to get on a Friday night ;))

      I usually check all my meters against each other, I really need a new meter… Family, if I put it on the Christmas list, would buy from a hobby shop (eg DSE, Jaycar, Altronics) and they do not sell quality (finally convinced the Ministry of finance that you get what you pay for) so what is a good brand, one that is as good as advertised ?

      • http://www.alternatezone.com/eevblog admin

        Fluke are of course still #1 in terms of quality.
        Meterman/Amprobe aren’t bad.
        Agilent make some very nice new meters
        How much will the Minister of finances allow?

    • Walter

      Thanks for the blog! You answered my question. When I first started listening, I thought I was going to have to send a follow-up question when you said counts have nothing to do with accuracy, but you answered my question in reference to the +/- count issue at the end. Thanks.

    • Kathy Quinlan

      lol Dave, you know minsters of finance, they want to spend as little as possible ;)

      Will go trawl some sites :)

      • http://www.alternatezone.com/eevblog admin

        I bet my Minster of Finance is 10 times worse than yours, mine’s FEMALE! :-P
        Shoes are an OK expense, but a multimeter gets a slap over the head!

        • Alex

          Of course… because shoes are a necessity while our gear are TOYS! :)

    • Kathy Quinlan

      lol dave, Mine is female too….

      Kat.

      • http://www.alternatezone.com/eevblog admin

        LOL!
        For some reason, this line from Under Siege 2 just jumped into my head:

        (Profanity warning)

    • Timothy Tee

      I saw a lot of electronic test equipment usually has ratings like ‘CAT III 1000V’ and ‘CAT IV 600V’. I know is something to do with the meter is more suitable on those level of power distribution but why this is important?

    • http://techrentals.com.au Multimeters and Electrometers

      Its good to know their accuracy are similar. although their design are different but they can provide accurate readings.

    • Paulo S Gon

      Thank you very much, from Brasil South America
      Very good!!!!!
      Paulo

    • Donald Petty

      What is multimeter resolution?