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  • EEVblog #173 – Gossen Metrahit Energy Multimeter Teardown

    Posted on May 27th, 2011 EEVblog 47 comments

    What’s inside Gossen Metrawatt’s Metrahit Energy Multimeter?

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    • Alexander

      What a beautiful design. They certainly have spared no expenses.
      I’m curious about one thing – what is that yellow goo on the side of the resistors, 13 minutes into the video?

      • http://toolhacker.com Wartex

        Glue from PnP

        • Alexander

          Is this common practice even when mounting “smaller” components (smaller than those huge thick/thin film hybrid resistors), such as 0603?
          If you look at the power monitoring board, the resistors and capacitors aren’t glued to the board.

          • http://thexmoschallenge.wordpress.com/ Berni

            They sometimes use glue on SMD parts when they use wave soldering since the flow of solder would otherwise blow them off the board.

      • Zoom

        Maybe is beatifule, but Metrahit, 29s & 28s are is most beatifule and functional.

    • Wardenclyffe

      How much is “paying through the nose” in this case?

      • djsb

        £598.80 (inc VAT) + £12 postage from GMC Instrumentation in the UK.

        • Phil Reynolds

          Nice meter. I looked at one of these the other week – thinking it would be a good one to have if my measurement needs become more advanced. I was unable to find it for under £900, but can believe it would be cheaper direct.

          The mod resistor caught my eye before you mentioned it – but then again, this is a German device, they’ll probably work that into later boards.

          Expensive replacement fuses – maybe that would encourage taking greater care not to blow or worse still lose them.

      • http://www.eevblog.com EEVblog

        You won’t get much change from a thousand bucks.

    • Coder

      I can’t see how those back-to-back MOSFET’s in the current measurement circuit could be used for ‘switching the fuse’. Perhaps they are meant to bypass (ie. short circuit) some other current sense resistor of higher value which is used for low current measurements?

      • chris

        Maybe it’s a fuse-protection circuit? ;)

        Regarding that dodgy resistor: “Sie werden sich hinsetzen! Sie werden ruhig sein! Sie werden nicht beleidigen Deutschland!” (Family Guy) *fg*

        • http://kj6ead.hackhut.com KJ6EAD

          “Sie werden sich hinsetzen! Sie werden ruhig sein! Sie werden nicht beleidigen Deutschland!”

          “They will sit down! They will be quiet! They will not insult Germany!”

          • rackandboneman

            This is ambiguous, it can also mean:

            “YOU will sit down! YOU will be quiet! YOU will not be insulting Germany!”

            You can not tell for sure with every “Sie” capitalized.

            And the last one is grammatically incorrect: It should read “Sie werden Deutschland nicht beleidigen!” independent of the meaning.

            The more germane german saying when it comes to meters is “Wer viel misst, misst viel Mist!” – “Who measures much, measures much c**p.”

            • Matthias

              I only know the shorter version “Wer mißt, mißt Mist” (Whoever measures, measures c**p). I believe it refers to the fact that every measurement will influence the measured value, something that will always be true, but must have been more important in the old days when measurement equipment had higher input resistance, etc. than these days.

      • Nitin

        The Back to Back MOSFETs are used to by pass the Shunt resistor , depending upon the Range. And its not the Fuse blow circuit!!!

    • ac

      I don’t understand. When you talk about “nice blast protection” at around 3:20, there’s a chip straight under that fuse slot? How’s that protected. Am I missing something obvious?

      • http://www.eevblog.com EEVblog

        When a meter gets overloaded with enough energy to blow stuff up, the last thing you are worrying about is the components surviving, all you care about is not having your hand blown off!

    • ac

      ^ Oh laughs. That’s explained bit later, it’s a sense resistor. Haven’t seen such as in here before!

    • Leo Bodnar

      I am getting a little bit fed up with multimeter and blogging equipment.

      Can we have some electrical ENGINEERING please?

      Thanks
      Leo

      • chris

        ACK.

        admittedly these teardowns are quite interesting – where else can you see which manufacturer you could trust your life?

        But there are many other things in ee – like: how to use design-tools (now Dave is “free” to rant about EDA-tools)?
        What can I use for filter calculations?

        “demystifying the black magic in smith’s diagram” ;)

        or something in the digital world i.e. running into fpga/cpld/…

        • http://www.eevblog.com EEVblog

          Yes, I have plans for all sorts of stuff like that, but those types of things take a lot more time and effort than a simple teardown and rant, so it’s hard to get into the grove for those. For example, everyone wants a comparison of EDA tools – great, so do I, but such a comparison would easily be a weeks full time solid work…
          And also, I’ve had this gear for some time so want to clear a bit of a backlog in terms of reviews/teardowns. And because I now usually do the teardown separate, it appears like I’m doing more of that than before (e.g. all the people ranted about the Agilent video “flood”).
          In the end, I still so whatever takes my fancy when I wake up in the morning.
          I expect a few complaints about my current video uploading now – a long winded monologue rant about the Renesas RX contest winners.

    • http://www.toddfun.com Todd Harrison

      @Leo Bodnar
      I must disagree! I look forward to every multimeter and test gear tear down and review. I learn TONS on what to look for when evaluating tech gear of all types.

      Dave, KEEP up the great tear downs and reviews PLEASE!

      Todd

    • Caleb

      I love the teardowns! When Dave gets excited (either because of something good or something that is completely ‘rooted’) it is always good video ;). Keep up the great work!

    • Wardenclyffe

      I love the teardowns as well. My favorites are the ones where the product is crap and Dave flips out (hilarious). I am hoping for another live show some time soon though.

    • Erickk

      I got to do FA on some pretty cool printed resistors this week. The ones I looked at were Ohmcraft, specked by customer.

    • http://www.waltec.nl Qno

      Hi Dave

      Looking for the fuse??
      Play back the video….

    • Phil

      Hi, Dave! Could you please do in-depth teardown of some programmable lab power supply? Like for example Rigol ones. Or even Agilent.

    • http://hackdev.com Steven
      • Phil

        You can buy it without review ;-)

      • rackandboneman

        So do I … don’t badmouth the cheap ones, show us what is wrong with them or not.

        • Phil

          That one is Uni-T it’s not so bad meter, but there’s nothing to review there. If you need a pocket meter – just buy it. It’s only $12.

          • http://hackdev.com Steven

            I don’t need a meter for the moment, I was going more for a comparison of insanely cheap meters vs. professional kit.

            • Evan

              There is nothing wrong with pocket meters, but they are not a replacement for a full size hand-held meter. You should have both!

              The Gossen meters are drool-worthy but in the category of ‘if you have to ask you can’t afford it’ — they are simply not targeting cost-sensitive customers. Just go back and check out Dave’s $50 and $100 meter shootouts and pick your two favorites and throw in a pocket meter on top — you will use all of them.

              The pocket meters are actually not all that cost effective. They use expensive and short lived lithium coin cells, often don’t have replaceable fuses, and if the captive leads are damaged the meter is toast. It doesn’t take many replacements to add up to $50 that can get you a much more versatile tool. Instead you should think of the pocket meters as something to use when the small size and weight are more important.

    • http://maggidev.com Ben

      The shunt resistors look like a Vishay CSM series shunt resistors, expensive stuff

    • Raff

      Dave, I reckon the fuse went to ‘sock planet’. I’m told on good authority it’s where all those single socks go when you wash ‘em. There’s also a biro planet as well…. Great teardown, keep them going, most of us out here cant get a hold of nice gear like that to look inside. I too like the way German gear is built.

    • Andreas

      Hi Dave,

      I hope you find the fuse.

      I blow up the fuse in my Metrahit Energy last week and find out that a replacement fuse for that Multimeter is very expensive.

      You had to buy a whole set of 10 for only €63 + VAT list price.

      I really hope you will find the fuse.

      Greetings from Berlin/Germany
      Andreas

    • http://e-motion.lt elektrinis

      No more multimeters, please. :(
      Any multimeter will do good in right hands. And any will do bad if used with left hands.

      Dave, I’d like to see more tutorials, theory. I know those take more time, but they are a lot more worth it.

    • Mal

      Did you look for the fuse inside the DMM case?

    • Ra

      Nice teardown!

      But will the last two teardowns be followed by two reviews? I want specs and comments of the specs!

    • Mike

      Hey Dave,

      This teardown left me wondering, why is it good to have relays in the meter? What are they used for?

      Also, does this meter have the input barriers on the non-common input for each function selection? I saw you showing them on another Gossen and was hoping to see how the mechanics of that work.

      Thanks. I’ve found myself watching your meter reviews even after selected and picked up a meter.

    • Daniel

      Nice VLOG.
      Did you know that Gossen actually features this on their website? Right on gossenmetrawatt.com in the bottom left corner.
      Awesome!

      • Daniel

        oh did I say left? it’s on the right side, of course! ;)

    • zappaMan

      Those FETs look like synchronous rectification to me.

    • Rick

      The FETs are probably used as the fuse funciton rather than just to protect the fuse. Especially with how expensive the fuse is. The meter measurement circuit can see it is over current and shut down the FETs — thereby acting as an open fuse. The fuse is for when things go wrong.

    • John

      I still like the meter melt down video posted on the Gossen site:
      http://www.gossenmetrawatt.com/english/seiten/cautiondangerousmultimeters.htm

      A plant electrician I knew thought he was measuring 1200 volts, but it was the 12,000 volts coming into the plant. “The meter exploded and vaporized” (his own words) severly burning his hand. No idea what brand it was. Many of cheaper meters have the contacts and circuitry under the rotary switch too close together to withstand much over voltage.

    • iurius

      Dave,
      Great show, but I’ve noticed you using the word “Pornography” certain times. Please do not use this word, as it, IMO, makes you sound cheap.
      That’s not criticism but rather an advice.
      Thank you!

      P.S. The original meaning of the word “Pornography” was “something obscene, unnatural, dehumanizing, animalic”. The meaning, however, has changed during time and is now as in the link below ( but how does it apply to your show? :) )
      http://en.wikipedia.org/wiki/Pornography

      • http://www.eevblog.com EEVblog

        I use the word pornographic.
        It’s a common colloquial term meaning something sexy, or to incite lust. I will not stop using it, because I like the term.