Hi welcome to the Eev blog an Electronics Engineering Video blog of interest to anyone involved in electronics design. I'm your host Dave Jones Hi it's product review time again. Yep, it's another multimer and we haven't had one of these for a while. It's a German Gosen Metrawatt made in Germany you beauty! What are these wacky Germans Been up to this time with the Metr Hit Energy.

It's part of their Starline series. very similar to the Metr hit X Ra uh System multimeter I've reviewed Donkeys years ago and this is the new Energy multimeter. Triple display measures power and energy consumption. It's brilliant.

It's one of my favorite meters on my bench. Let's crack it open and see what's inside. Here it is up close. It uses exactly the same case as the Metr hit uh, extra series which I've reviewed before but of course it now.

It measures Energy power watts VA um power factor and all sorts of stuff voltage and current at the same time and that's why you've got the triple digit display up here which is beautiful I Love it! It's got full count and resolution on each display. Beautiful and it's exactly the same case. It's got the IR interface and the same tiling Bale and everything else there it is made in Germany Got to love it. Love German Made gear Uh, it's got a separate battery compartment up here, separate fuse compartment, and a couple of um Security screws down the bottom which will crack open and see if we can get inside the case.

and there you have it. You open it up and you immediately, uh, like the construction except for one glaring thing which you are immediately drawn to and that is a mod resistor on the back of this board. here. look at it.

Um, granted I Do I believe I have like an early Uh unit cuz I've had this one for quite some time, so um I would presume that they've uh, sorted that out and they've upgraded that in their production boards. I may even have a pre-production board or something like that there. Um, but as you can see, it's uh, two board uh construction with the input circuit here, which looks quite nice. Let's take a more detailed look now.

what looks like At First to be a two board construction. Here, it's not. It's actually a three board construction. There's a third board under there, presumably a display board.

uh, going through that connector there. and as you would expect, there is complete o-ring protection right around the outside of the case. but uh, the main uh top part of the case though does not have really deep uh ridges on it. uh, for you know, maximum blast protection.

but uh, Gosson do know what they're doing in this area. They are one of the leaders in Um multimeter input protection and stuff like that. so I'm sure they know exactly what they're doing and they've done the right thing with this uh, fuse compartment design here. There's an extended Uh part here which mates up with the Um isolation slot high voltage isolation slot on the board here, so it's for blast protection as well as Arc over uh protection as well the Um input, side and ground.

That's a really nice design. I Like it. There's one thing goon's done, which is interesting. on the Uh DC input jack.

here. it's highly recessed on the back of the case, and presumably that's to stop the connector when you put the connector in there. it's to stop it um, shearing off, uh to actually give it some, uh, stress protection. So that's a really nice, uh, really nice um aspect of the design and you can see the extended tube here for it.

but unfortunately it does go out to just basic flying leads which are just, uh, hand soldered onto the board there. I Would have much preferred to see a high quality connector there and the input Jacks here. I Really like they're quite a unique design. They got a single, uh, solid piece coming out of here with a a single uh integrated lead coming out and then it's fed into a slot on the board like that and then hand solded down there.

There's a bit of solder residue on there, but it's not a big deal. Um, so that ensures a rigid connection because it's um, actually gone through that slot and held in place with that slot. So it's really quite nice. and there's automatic Um isolation between uh, the front side and the back side of the board here.

and it's just. it's really quite nice. As you'd expect with a top quality Gosen meter, you get a ton of input protection. Here's some high power input protection resistors.

uh, a couple of PTC poly switches here and here, that's your AC input, uh coupling cap. You've got a couple of gas discharge tubes here here surface mount versions. Nice to see you've got a Mau here. and curiously, there's a couple of uh, what looks like half amp fuses here and I'm not sure what they're actually.

uh, protecting your guess is as good as mine. I've removed the main fuse here and you can see the current, uh, sense resistor under there. and they've actually used a proper surface mount four terminal current sense resistor instead of the bent piece of metal. Basically, that, uh, almost every other meter uses and you can see the um extra.

You can see the voltage sense terminals there tapping directly off that, directly off the terminals or the pads of that resistor and that's the proper way to do it. It's really nice now. Curiously, there's a couple of uh, mosfet big Power mosfets here like this, which, uh, switch the fuse now I did a quick check and I've actually got a Dave CAD drawing of that here. Let's so let's take a look at it.

Here's your amps Jack over here and your ground. uh Jack Here, there's your 10 mohm four terminal current sense resistor there, the uh, those that voltage goes off there to uh to a differential amplifier and these are your two mosfets. They're an IRL um, 2203 and a pretty uh standard device. It's a nice device.

It's got a 7 mli ohm on Resistance very low 30 volt rated 116, a big beefy power mosfet and they're put back to back like that. and of course there's internal uh, parasitic dodes with that as well. Now this secondary board here that's uh, rather interesting. you don't see that very often these days and I like it.

It's just uses uh, a standard 0.1 in pin headers like that. It really is quite nice. The Circ there we'll take a look at, but uh, this is actually the Uh Power monitoring Uh board which enables all the um, all the Uh, power factor correction and energy monitoring devices. This device here is actually a uh, it's hard to get the number on that, but it's actually a Cirrus Logic CS 5463 and that's a Biral Power Energy monitor IC specifically designed for uh, this application so they've used as you would you would use an off-the-shelf chip for this.

They've already perfected the Energy Measurement technology and and the various techniques used to measure all that sort of stuff. so it's all on chip. It's got a building voltage reference. this is just support circuitry I'm not sure what it does.

bunch of Op ants, few transistors and things. pretty much, uh, discreet stuff. but I uh, rather like that board. the bodgy resistor I don't know I'm going to assume they fixed it in the production version I'm not going to mark them down for that because well, I don't know, it's Gossen and well, they actually have, um, a a history of doing us Germany German Companies like to make mods like this.

It's not unusual at all, but I'm sure they've fixed it and check it out. This brings tears of joy. We've got two high sensitivity 3vt reays on here. real manly reays that you switch stuff with.

none. This electronic switching stick in a Reay I Love it. When you turn the rain switch and you hear that click of that relay, you know you just know it's designed and it's going to measure properly. I Love it.

And if you're wondering what this device here, it looks rather curious. I've uh I don't think I've ever seen one of these before or very rarely. but what I believe it is is I believe it's a um thick film hybrid Precision resistor and I measure it and it's pretty darn close to spot on to 20 megga ohms So um I believe that's what it is and uh, it's just unusual because one thing you won't find on this board overall is a thick film Precision Hybrid resistor Network So obviously they're um, well, that that's probably one of them and maybe they're using some discrets I Don't know. But as you can see, the rest of the board is lovely constructed.

the uh, lovely. Nicely laid out, the soldering, the construction, the components are first class. We've got a a couple of Um surface mount electrolytic caps here. There's a couple of Tanms in there as well.

There's lots of 40 4000 series are switching like there's some Max 4053 devices. Uh, down here, there's a Max 4052 over here somewhere and this device down in here is actually the true RMS converter chip and they haven't used the Analog Devices one. They've gone with a uh Cirus Tech Um brand which is a I Believe it's a Taiwanese uh brand who do multimeter chipsets. They also do a uh true RMS converter chip and it's the Es 636 which presumably is uh, maybe uh pin compatible I haven't checked.

probably pin compatible with The Analog Devices Parts cuz as you can see, they put in a dual footprint there, so maybe they can, uh, decide at at the time production whether or not to use the Sirrus tech one or maybe use a different package or a different brand entirely. No major surprises whatsoever. The main processor is a TI MSP 430 low power 16bit micro and uh, there's another device here which might be a custom one I don't know, it's got a sticker over it I'm going to have to take that off. Uh, there's a bunch of other uh, discret um, just, uh, discret devices around here.

There's nothing, uh, terribly interesting there. and the battery terminals are lovely. The ablea battery terminals solded directly onto the board I Love it. There are three uh, three terminal Mount like that.

Really nice. and they've got a proper uh, through hole buzzer like that. none of this external little uh peo crap which is stick on the side of the C with a couple of flying leads. and there's the infrared transceiver.

Now, curiously, it's actually a fair distance back from the Uh window on the back part of the device here. but I guess that's not a big deal. It still works just fine I've taken the sticker off that chip and I can't see any identifiable markings at all. There's a bit of residue on there which I can't get off, but I can't see a thing.

so maybe it's a fully custom Gossam basic. Who knows Gossam, You got an answer on that one. Well, I'm trying to get this top board out here and one of the really annoying things is that it looks like you have to desolder the input connectors here before you can actually lift the board out. What a bummer! There we go.

I've desoldered the Uh three terminals there which was actually uh, quite easy. and Tada there we go. It lifts straight up and we can access the bottom board. And here's the famous Gossen Range switch.

That's how they implement it. They've got springs either side here with large notches and this is how they make it feel and sound so magnificent when it switches ranges like that and the positive retention you get on each one. Oh, it's just pornographic. It really is.

And here's the bottom part of the board. They've got extra some extra power resistors on here. They' got this large uh, metal shielding can. There's not much under there, there's just pretty much, uh, more of the same.

They've got a whole bunch of other uh, passive devices on the bottom here, and not much else really. But um, yeah, there's quite a significant amount of extra passives on the bottom side. There you go. There's more hybrid resistors on the bottom here, a couple more there, a couple of Meg each.

and and there's another device down here which looks similar. It's uh, green, uh, coated with like a green mask on it, which looks different to those, but it's a the the uh. The tracking work on the top is identical, but that one is not high value. That one's around about2 ohms or thereabouts.

I've swung away the top uh LCD board and once again, they spared no expense here. Instead of just um, the rubber membrane type uh interface, they got proper tactile surface mount switches there. Beautiful! And the LCD just isn't a standard uh LCD a cheap LCD uh with just the uh zebra strip for the contacts. It's actually a chip on board.

Those those two little uh things you see down in there are actually the uh chip on glass. They're actually the chip Chips mounted directly on the glass. and as you can see, there's not many connection interfaces. There's just a a few down here and a couple of extra uh support ones uh, top and bottom here.

And that's actually got the circuitry built on to drive all of the many, many hundreds of circuits for the Triple digit display on there. cuz really, uh, without that, you wouldn't you have a hell of a time driving it from just a generic micro. It's just got too many segments with that triple display, so they've gone to a lot of effort there to do a fully custom uh chip on glass or Cog display it's called and I've put it back together. It all works, of course, but listen to these lovely reays.

A Isn't that just beautiful? Let's hear that again. Ah, after tearing something down, there's usually a screw left over, but not in this case. I'm missing the fuse for the life of me. I Have no idea where the thing went.

Unbelievable. One thing which uh is hard to get a a real gauge of is the quality of the Plastics used in the construction. but you can just uh. after a while you get some experience.

you can just tell that this is a real high quality ABS Probably an impact resistant, uh polymer type uh ABS material. Real high quality, uh stuff. as you'd expect in a high-end meter like a Gosset I'm sure they spared no expense. It's not those cheap brittle Plastics You get in the real one, hung low brand meters.

so there you have it. That's the Gossen Metri Energy multimeter as you'd expect. Superbly designed and built I'm thoroughly impressed. That dodgy resistor aside, well, you know, I'm sure they'll fix that, but there's no excuse for that.

But anyway, unbelievably good. I Love the quality, the design and the construction, but you pay through the nose for it, so that's what you expect. Now Where's that freaking fuse man?.