Hi welcome to everyone's favorite segment Mailbag! We've got a multimeter. Thank you very much. uh, Zotek Instruments for sending this one in. Of course, Zotek are uh, famous for making, um, pretty much most of the uh, you know, decent, really cheap.

like you know, sub 50 bucks. like 20 multimeters and those Aining brand ones there actually? uh, which? I've done a video on that 20 meter? They're actually um, Zotek. So Zotek have sent in their latest meter. It's just released so let's check it out.

Oh sorry Giant Knife Aficionados are going to get upset that I didn't actually use the knife. so let's get in here. Oh look at this. doesn't this look Schmick It looks like a multimeter, but it's actually Um and oscilloscope.

It's a digital oscilloscope. It goes for like under 80 US bucks. In fact, the street price I believe is even going to be less than that comes with the pouch. Let's see, we've seen these um El Cheapo pocket uh oscilloscopes before and they're usually pretty crap.

Um, oh geez. Okay, thermocouple probes. They look pretty standard that you get with all the uh, Zotek jobbies. And we've got one oscilloscope probe.

Looks like a genuine switchable. um, even though they've been banned. Got the alignment tool, couple of color adapter rings, but this is only a single Channel job. It's It's a large, quality, cheap probe.

As you'd expect, we get a USBC cable because interestingly, for those who've been screaming out for it, we'll take a look inside, but it's powered from a an 18650 lithium ion rechargeable, so let's whoa all that off. Now it? does actually have Zoe on it if that's how you pronounce it, but it's actually uh. Zotek is the actual uh company. So oh, look at this danger.

Will Robinson stopped testing voltage in current mode. Don't do it, Don't do it I Just tweeted the other day somebody actually, um, uh, tried to return on Amazon one of my EV blog meters. Um, because the current range just suddenly stopped working. Uh, they didn't realize that there was a fuse in it that would blow in things.

So maybe they've had like too many people actually return it because the current functions stopped working because they didn't realize what a fuse is. Anyway, that looks and feels like a decent meter that is, that's pretty robust. I Mean that's it's. got a little uh, molded rubber surrounding there.

Um, it is curved like that so if it hits that, it's just gonna rock around and it's gonna, uh, you know there's no like impact, uh, points or anything like that. But it's fine. We've got a cat 2 rated uh, standard B and C input for our oscilloscope function. Got a tiny user manual Note: If there is a freeze or crash during use, please restart.

Okay, well granted, this is like it's I don't even think it's actually released yet. It should be incredibly shortly. Uh, if it's not already. but uh yeah, there you go.

um I'll leave it down below. it's got all the various modes and things like that oscilloscope function probe check, vertical triggering systems, horizontal oscilloscope measurements. so it's got to probably automated measurements and stuff like that. Um, and then the multimeter interface with the wanky bar graph and everything else.

Now, the meter itself are ten thousand counts, so that's not too shabby. Three times a second update in true RMS and it's an anomaly. Half a percent? So it's not like a lab, you know. Quality? Uh, meter.

But for the price? Absolutely brilliant. Does have a 10 millivolt range. one micro volt resolution? Absolutely. Uh, fantastic.

So that's very handy. Only point eight percent or one percent are current plus a few digits. Um, unfortunately only has a one micron amp resolution, so that would have been nice to get a bit less than that. uh, resistance up to 100 Meg capacitance up to 100 Milli the oscilloscope 48 Meg sample wire per second.

It's got AC DC coupling sine X on x, interpolation 64k of memory, and a 10 Meg analog bandwidth for your 48 Meg samples per second. So it's going to be a real-time Joby Of course, something like this, you know, a portable oscilloscope for the field 10 megahertz bandwidth. If it actually, you know, does that reasonably, then that's not too shabby at all. That's still very handy bit of Kit Remember what we say here on the EV blog.

Don't turn it on. Take it apart. Oh, metal threaded inserts. Win a Win a chicken dinner? Um yes, it does have a uh probe cowl here.

and there's the USB C there so behind a little rubber baby buggy bumper there. Unfortunately, the fuses are inside and the battery is inside. but it's uh, of course rechargeable through the USB so no workers. These screws in the bottom refused to come out so the top ones did though.

So let me if I have I missed, one might need spudger. There we go. Yep, there are a couple of plastic Clips in there. we're in like Flynn Look at that.

that looks neat and tidy doesn't it? Wow. not much doing in there at all. but obviously you can see the split in the grounds between the oscilloscope functionality it looks like the USB charging and the battery is tied to the uh oscilloscope ground so they will be common. We can probe that out, but you can guarantee that they're actually going to be a common ground I think and it looks like look at this.

uh, this looks like a little uh, isolated uh converter down here. and um, yeah, we're just getting uh, serial data over there. But as I said, there's an 18650 in there. but jeez, a real hard time getting that out.

But there you go. It's a Yin lithium ion. um, two thousand milliamp hour. But yeah, you know if you want to put a better quality or a higher capacity one in there and our input Jacks here look okay for the uh price category.

they're not uh, split, uh Jacks at all over here, so it looks like it has no input. Uh, or split Jack uh. Input alert. Little M205 fuses here, but they are ceramic jobbies so that's pretty good.

Um, not a huge amount of protection. We've got a a real Fed Income relay here, so that's not too shabby. but yeah, basically. uh to input uh MILF series resistors here, and a tiny little uh PTC there.

And so unless there's mobs on the other side. uh yeah, not a huge amount of protection. So the Cat4 600 volts Cat 3000 volts. yeah.

compare this with, say, the Bm786 which is exactly, uh, the same specification as that. and I'll put up the photo here, the input section uh, on the 786 and just compare it to the one piece. CC with no mobs. Yeah, there's just no contest chicken phrase here here.

Gold. Okay, I've taken off the four Jack screws. There's uh, six self-tapping screws in here, so this should. Well, yeah, it's going to come out as the one assembly and flip it over.

Yeah, there's no extra protection on the inputs under here and all the processing is under there. or the oscilloscope and the 80s sampling and the ADC and everything else. But yeah, um, as far as the multimeter functionality goes, yeah, it's it's very basic. Um I Don't think this is.

uh, you know, gonna meet its uh cat rating. It's probably good enough for basic Mains use and we'll have some testing in a minute. But for industrial use? yeah, no for the reference Fanboys Icl8069 Jobby: uh, whatever variant that is the multimeter chipset dm1109 there doesn't ring a bell, but of course. uh, Zotex founder Lee Hong He's actually uh, famous for developing a lot of, or you know, helping out with the development of a lot of the multimeter chipsets that a lot of people take for granted these days.

They're actually one of the Pioneers in multimeter chipset, so this will be their own. Joby So we're going to USBC input over here. Looks like we've got just some diode protection there, some charging stuff, a couple of over miscellaneous jobbies over here as well, and a little front end can there that looks sold down so we may have to get medieval on that one. but if we flip it over, then it looks like we've got an E-square prom here, and a processor and another metal can.

All right, let's take a look at the front end here. I've got the main can on the top often I've got the main can on the bottom. Not all the tabs were soldered. That would have been a tad more difficult.

So what we've got here: the main processor is an artery I Don't think I've heard of this before, but it's an At32fr403 and if we go to the videotape over here, this is an Arm R based 32-bit Cortex M4f Joby 256 to 1 Meg Uh. Flash has got USB can eight in time, three Adcs, everything else. It's got up to 96 or 128 kilobytes of S Plus 128. It's got a separate SRAM or something.

but anyway, we've got the ADC which we'll have a look at, but there's no other glue logic in here so there's no CP or D fpga or anything. No sample memory. Uh, so the 64k a sample memory must be inside here and this must just be sampling in real time. We've got an old school Art 4051 analog mux down here.

Looks like we've got an attempt at a standard, um, analog. uh. front end. This is our B and C of course.

Then we've got a little, uh, solid state relay. that's the AC coupling. so that's your ACD and when it's DC it just shorts out the uh cap. Um, it looks like we've just got a ground resistor there and it looks like, yeah, we haven't got our traditional analog front end because if we flip it over like this, but you wouldn't expect it, right? This is fairly, uh, simplistic.

This is only 20 millivolt per division. Two? What? 10 volts per division? Anyway, we have another relay under here. that's interesting. We've got a trimmer cap there for our compensation.

Um, and we've got like a fat or something there. Yeah, but that's basically it. So there's no like, uh, variable gain amp. you know, program will gain amplifier or anything like that.

We've just got basically going through a uh divider here. We're using a 4051 analog mug straight into here. So it's not the best analog front end, but what do you want? It's a sub 80, right? So you get what you get and you don't get upset. Anyway, the ADC here is an MSR 9280.

This is interesting. hadn't heard of this one before. This is a hangs you a rooming Tech Um, and it's available on LCS. So you can get this puppy in thousand of quantity for 86 us cents.

And none of this 8-bit rubbish. It's actually a 10 bit 50 meg sample per second. ADC I Didn't readily find an English uh version of this, but one may be available. There's the architecture for those playing along at home and there you go.

So yeah, 50 megahertz, um, bandwidth. And there they're just running through a resistor divider ladder. Yet there's nothing on the that was over here. so there's no compensation on that resistor.

Network Bear there. but that would be an attenuator and there's some compensation possibly uh, across there. But yeah, it's just sampling that in real time. No worries.

Good enough for Australia Good enough for an 80 Buck Uh meter. You know the proofs in the pudding how well it's implemented. Anyway, as I mentioned, uh, metal threaded in search which which is, uh, really nice. And then we do have uh, some grooves around here for uh, blast protection.

so that's all right. But yeah, you wouldn't be using this thing and in an industrial environment I Mean just don't believe the cat raid in. of course it's not independently certified. Let's go.

Zoe Well, that's quick to come on. There's the battery indicator. It booted up in scope mode I Don't know whether or not that's always going to. Well, let's try it.

Actually, how do we turn that off? There you go. Will it boot back up in multimeter mode? You've got to hold it down. Okay, maybe that's for no. Come on, you want it to go to multimeter? Mo You want it to go to your last mode I reckon.

Anyway, you can see that there's like a bit of wanky red tinge under the bar graph there. no give me bigger digits. Please don't give me the wanky bar graph and everything else. You've got room on there for super large digits.

Do it anyway. I Don't mind the interface. there's the mode button Only does two things. oscilloscope, multimeter.

That's it. And then you've got your function button. So you've got your Uh DC AC There you go. It doesn't have DC plus AC but in this class of instrument, we'll uh, forgive that.

There you go, there's our Ohms that didn't look uh, that quick. For the auto raging, there's a current test. I Love how it warns you. It's gonna warn you every time.

No, it doesn't. It only warns you that once. That's nice. Pay attention to the current.

Jacks that warning sticker. They've obviously had too many people like blowing the fuses, complaining that the molding meat is crap and doesn't work because they don't understand what fuses are and how they work. and well, I have encountered it. So yeah.

So yeah, there's your one microamp resolution there. there's your true. RMS AC Also, one micronet resolution, but the the interface is quite simple. I Rather like it.

you've got your manual. ranging. doesn't looks like it doesn't have Auto hold or p-cut like it's just got hold and that's it. It doesn't have like any.

uh Peak hold range. Yeah, oh. the probes. Check them out.

They are exceedingly long and sharp, but they're not. They almost look like Pogo pins. but they're not. No, we can't pull them out.

They're rather unusual. anyway. they're not gold. uh, plated.

So yeah. okay. Continuity mode. that's pretty quick.

Latch in nice, that's excellent. And in multimeter mode, these Arrow buttons do nothing. but the menu actually does. Uh, come up so you can get English Auto off.

Okay, get rid of the auto off. Uh. backlight. That's all right.

I'll turn the lights off. hang on. a bit darker in here. now.

there you go. You can see more of the wanky red background there, but like how it tells you the version number Ohm's range response: Yeah, I didn't expect it. That's not bad and we've got uh, 10 milliohms as well. That's not too shabby and it is giving you Max Min average.

But I don't see a way to reset that we're going to hold can we? Oh yeah. Oh well. I'll take a picture. Look at this, it takes a bitmap how do we go? We can obviously connect that to the USB That's probably how we do the firmware update as well.

It might be handy for documentation. Well, it's not far off on capacitance. That's well with inspect. Oh, look at that.

Practically bang on on the resistance. Oh yeah. one volt. hang on 100 millivolts, Bang on 10 volts.

Bang on. uh. hang on. What's going on here? It's supposed to be one milliamp.

I'm getting 110. If I go up to 10 milliamps, it says 1.1 amps on the on the milliamp range. What? Uh, get back to you, there's a sanity check. What the heck is this thing doing All right using the 10 amp? Jack It actually works.

There you go: 10 milliamps, but it doesn't work on the milliamp Jack What are you kidding me? I Mean why would it even display amps at all in the milliamp range? That just that doesn't make sense at all And like and it doesn't even scale properly. It's 10 up there on the bar graph whereas it's actually one here. So like that doesn't make sense. So they're not actually changing the bar graph to match the range.

What? the Yeah? So they have this fancy bar graph and it just sticks from from 10 to 100. Regardless, it looks like of what um, like mode you're actually in and what range you're in like there's I'm on Resistance now and I'm going through and the bar graph doesn't change. Oh no. Oh, hang on I figured it out.

Look, it's I'm I'm actually in Amps mode here. If I switch to Milliamps mode, it works. It's bang on. But why you could have it in Amps mode and put the Jack in the Milliamp Jack and get that Um rating.

The fact that that's actually possible and gives you a higher reading like that? No, that's that's unacceptable. They need to somehow eliminate that possibility. And by the way, it's called Uh Milliamps even though uh, by default, that's actually the microamp range and the Milliamp range is actually only um, 50r. Bloody.

It's ran out of battery already, so that's some sort of design. Quirk They really need to make sure fix that and make sure that is not possible. Anyway, there you go anyway. 100 microamps.

It's all bang on, but just pushing the button like that like you know you intend to measure a Milliamps, but you've accidentally got it in Amps mode like I Don't know of another. Please leave it in the comments. Do you know of another meter that actually can do that? I I Don't know. Like wow.

3.2 volt. Uh, compliance. In Diode mode, that's pretty good. That'll turn on like a white lead.

Yeah, there you go. Lights it up. Anyway, as I said, it does feel pretty sturdy and the display is not going to get damaged. That's going to take some impact there, so that's really quite.

Jazzy And uh, The Tilden Bail on it. Uh, it's a bit. It doesn't flap it around in the breeze there. Um, yeah, no, that doesn't instill a lot of confidence really.

but you know it tilts we here for what we're paying the money for, all our 80 Yankee bucks for is uh, the oscilloscope here and I like the interface here. and I like this when you're in Vault time mode, just up and down changes your 10 volts per division. Five? It's not. uh, one, two five.

It's actually two and a half and then two and then one. That's interesting. 500 millivolts. I Can hear it.

the relay click between 200 and 500 millivolts. So yeah, that's where they're just choosing the front end attenuation. And of course, this issued time base. So 20 seconds per division? uh, goes this way down to 50 nanoseconds.

Uh, per division? That's that's what you want. And then you can move the waveform around. presumably. Yep, we can move it up and down.

If you double click, it Does it? Go back? No, you want to be able to reset it, but that's okay. And then trigger is just going to adjust your your trigger level with your green. Is that going to vanish? No, it's just going to stay there. That's fine.

And then you got your AC and DC coupling over here. Brill. Brilliant. and we're gonna probably have another menu.

Yep, Um, AC and DC coupling. Uh, we've done that. normal auto mode: Single shot capture uh, trigger, rising, fall in, and times one times ten Pro That's all you need. Fantastic user interface.

The update looks, uh, frequent enough. I Would have liked to have seen like a bigger cut out here because you'd get in there and difficult to sort of screw that in. It's not a big deal, but just notice that everything on this probe spins. Um, including the the tighten up thing.

Whatever it is. Um, that just keeps on spinning all right. Got the probe hooked up times 10 to mode here. Let's press the auto button.

Yes, it does have. Come on, you can do it. She's taking his time hurt the relay. Go there.

Bingo. We will calibrate our probie shall we? So let's hold the tongue at the right angle. There you go and it retains its shape even when we click the relay. between 200 and 500.

So that's all right. Square Wave signal Fidelity One Kilohertz is all right and it's giving us our measurement. One kilohertz. Uh, the three volts.

Uh, Peak to Peak uh V Max that's actually from that'd be from the ground, so that is useful and that is quick. We can't cause that to Alias Nope. Wow. So far, this looks very useful.

Wow. Looks like it's implemented reasonably well, especially for the price. Now, we do seem to have an overload issue here, so 200 we'll switch down to the lower range and then if we try to go higher, it's got some weird artifact. so I'm not sure what's doing there.

It's not terrific, but not unexpected. I Guess we'll check this out. I Just noticed that the trigger level does not match. Look, the trigger level is above the waveform there and if I go down like this, it'll actually lose trigger even before the bottom down there.

so it's like it's still there. but it's yeah. So the calibration of that slightly off. and check out the coupling when I switch from DC to AC here.

Um, it's taken its fat time. What's going on there? It's almost as if it's like hasn't got the one big input impedance. and I there is a calibrate mode so you can go through some extra menus and stuff Storage: enter Oh, is that how you ex enter the USB drive mode goodness because I couldn't get the screen capture off here. let me go and try it.

Yeah, that worked. To get your images out, you've got to go into oscilloscope mode menu over over and then you've got to go into storage mode and then you can, you know, access the files under. Windows just appears as a drive. No worries.

works fine. So if I go into normal mode, how do you do single shot trigger like we're in single shot trigger and you would think that trigger would trigger it? Aha, that was not obvious. It's the hold button. The hold is the trigger button.

So I I guess it's under there. So yeah, all right. yeah, no worries. I'll tell you what would be nice though when you're in like a trigger mode like this.

Okay, you can't move, you tie it. You can't adjust your time base or your horizontal. That should be like. they should put the decals on here for example and you should be able to access those regardless of the menu or a syscept if you're in move menu.

I Guess you've got to actually go back to Vault time over here before you can actually adjust it. But yeah, all right. So let's try deep memory. Let's go.

Uh, 50 milliseconds uh, per division here and we'll go back into our trigger and we'll single shot capture that we can zoom in. Yeah, we've got a decent amount of memory 64k normally. when you're doing that though, you would change your window display up here to show sort of like what segment of the memory you're looking at. So it's like they're not updating that in stop mode so we can turn those extra functions on.

We've got uh V Min RMS and uh PRD which is actually uh, period. but they do actually overlay the screen there. That's why they don't have those on by default. I Really can't get enough purchase to screw on my T adapter here.

Ah I Had to actually use a pair of pliers and I can't get it off either. So I've got to use my pair of pliers to get it off and on. Oh no fail. I'm feeding in a one megahertz Square way 358 millivolts.

uh Peak to Peak is 300 and three six like, you know it's it's near enough. Even if we go off range, you can still still measure it, but you can still see the triggering is going a bit bit how you're doing there. Well increase the frequency. Let's go.

It's supposed to have a 10 megahertz bandwidth. There's our our Square wave has turned into a sine wave. Well tell you what, the thing won't Alias though. Well, it actually does have a 10 big bandwidth.

Uh, I'm feeding in one volt uh Peak to Peak where 0.82 Um, so we're not pointing at the minus three DB point of 0.707 yet. So back to our Square wave Again, that's seven Meg Let's go down. let's just say five Meg usable bandwidth. But as I said, it's still handy and it's actual signal Fidelity seems actually pretty good over all the Rangers and at the lower star 20 millivolts per division, there's a 50 millivolt uh Peak to Peak and we still get that at five megahertz.

so that's all right. So it's like signal Fidelity pulse response uh, up to five Meg is is quite reasonable for a little pocket instrument like this. and I like how the interface works, it's just fairly intuitive. The only extra thing I'd like to see is you know, in some modes I'd like to see the Vault time, um, still operational, but but it's not too shabby at all and it does have that uh, over range issue I'll just show you that with a triangle wave like this it does all right, but you get to a point where it will actually kind of like go nutso like that because normally you would use a scope saying well, once you see a signal off the range like that.

but if you had your range wrong in use all of a sudden saw that you would think that oh, that's not off range, that's actually a real signal. Something's really, really happening there. Is that my, you know, what's wrong with my product that I'm testing? um when there's actually nothing wrong with it, you just um, over ranged and you can fix that with a range issue. So yeah, it's not great, but yeah, maybe like maybe that's a firmware fix.

So we're running through the calibration now, so hopefully that'll do like an offset and maybe that'll fix that. Uh, trigger level? Um, issue that slide offset in the trigger that we actually had and stuff. No, it's still slightly off. See how that trigger line is above the triangle wave and quick multimeter test can actually survive a thousand volts.

Shows red up there for a hundred volts. because it is. Remember a thousand Volt Cat 3 Rated a thousand? Let's stress it a bit more. Oh, overload.

Take it back. Take it back. Take it back. Yeah.

Okay, can it survive 240 volts on the Ohms range? There's the AC So 245 volts here in the lab. Let's switch it to Ohmski. Yeah, it's do you don't expect it to do anything and then let's go back. There we go.

Yep, survived. Still message capacitors fine and it still measures resistance fine. So yeah, it's robust enough, but yeah, you wouldn't use that for industrial setting. Okay, it's measuring the standby current.

three microamps, sniffer of an oily rag stuff. All right, let's power it on. This is tricky: I Need multiple hands? Oscilloscope Mode: 350 milliamps Multimeter: Mode Still 350 milliamps of course. Processor drove in the screen.

Everything. So yeah, how long is that going to last? Well, for a 2 000 milliamp hour battery, um, that's only going to last like 5.7 hours. Let's say let's call it five hours. maybe a bit more.

A few more if you put in a higher capacity you know, better brand job or something. But so if you're just using this mainly for its multimeter functionality, you're not going to get a lot of hours out of it. You're really paying a premium in battery life for that oscilloscope, unfortunately. but there's nothing wrong with just having this in your fuel kit just to use as a basic oscilloscope.

And well, you might get some bonus multimeter functionality, but you might have your real multimeter in quote marks, um, in your bag as well. So the verdict on the Zotek: Zoe ZT 702 s digital oscilloscope slash multimeter and well. I Can't give it a thumbs up because it completely failed. Um, this.

it's the multimeters. Adequate enough. It would have been nice if the multimeter had some more uh, functionality, but you know it is what it is. But the main feature of this, and because you're trading off that huge battery life is of course the oscilloscope and it works alright.

There's a few issues with it that maybe they can, uh, fix in firmware, but the usability of it's actually better than those other pocket. Scopes And you could do some more extreme testing on this. Like, you know, what is the maximum voltage that, uh, before breakdown of the com Jack compared to the isolated oscilloscope over here and stuff like that, so you know from a safety, uh, point of view, it's probably okay that you know this is this ground is electrically isolated uh, from the common over here, so it's okay. but you've got to remember this is like 80 bucks retail.

You're probably going to get this as a street price I have seen one Uh, Company sell it. Supposedly that Uh has stock of this new model for like 60 bucks. So assuming that they can fix a few issues, it seems quite, uh, usable and seems like it might be. uh, decent value for money.

Worth considering in any case. But as with all these types of combined instruments, you know, jack of all trades, master of none. it's not a real good uh, multimeter and it's not a terrific oscilloscope, but it doesn't suck. I I don't know.

Anyway, I gotta I'll keep you updated. uh second Channel videos. If you want me to do more testing and stuff like that, leave it in the comments. but yeah, no, it completely failed the milliamps.

I Have no idea what's going on there. It's got a short battery life and but it is rechargeable. you know USBC you're going to have one of those. You know you're going to have a battery Bank in your kit anyway with a USB C cable for charging your shoe, phone and whatnot.

anyways, so it has the potential to be a reasonably useful bit of Kit especially at the price point. It's all about the price point, of course. So anyway, if you enjoyed that video, please give it a big thumbs up. Let me know If you want me to test more like low-cost instruments like this.

Catch you next time. Foreign.