Ah, Hi I thought I'd have a play around with this that you've seen before. I'll link in the video if you haven't I seen, it'll be at the end or down below. This is the Unity Ut5 1/3 insulation tester and this thing actually goes up to R5 kilovolts so 5 kilovolts, 2.5 or a thousand or 500. So I thought Ah, could this be potentially useful for you know, doing some very crude impulse overload testing on multimeters? So I thought I'd Give it a try, but to do this, you have to be able to see the waveform.

Yes, it can generate 5,000 volts into a high impedance. That's its job, but when you put it into a multimeter, they've got the mods in there which will clamp down and potentially like, essentially go low in. Peters short this thing out and we just don't know what is going to happen. Most likely it's going to clamp to the mauve voltage inside here and this would have enough output impedance to actually continue to drive that anyway.

I Thought it'd just be interesting to have a look. so I don't actually have anything that can measure 5 kilo volts here at the lab? Yeah. Cobble together a do-it-yourself high voltage probe I link that in down below and my Eevblog H Vp 70 probe if you haven't seen it. sexy as 70 megahertz, but it's only a basically a seven hundred volt probe is designed for mains.

you know, safe mains use and stuff like that discount coupon code linked in down below by the way. Anyway, so what I've got I've got this from my Charles at Trio Test, thank you very much. Charles You loaned this to me. It's the pin Tech HPP 15 H F Yes, it's a high voltage probe.

Let's have a quick quiz at it. curiously. on the card here, it says 50 megahertz, 3 DB bandwidth, a thousand-to-one attenuation ratio basically a 15 kilowatts DC 30 killer to peak or ten kilovolts RMS But if you go in here to the menu, curiously, it says it's only 40 megahertz and only ten kilovolts with a 20 kilovolt peak. So I don't know what's going on there.

Any a bit of a discrepancy. Anyway, it's a fairly cheap and fairly nice high voltage probes, so this will be more than good enough for measuring the 5 kilohertz coming from this puppy-like So let's have a look and see what we get. Alright, so what I've got is I've actually aren't set my probe here to a thousand to one you can set up. This is on the road.

In short, our CB to double over. so we're one kilovolt per division now. so I'm just going to go ahead and our single-shot trigger that I've got to set the five kilovolts. Let's switch it on and see what we get.

I haven't got a hooked up with a multimeter so it's just hooked up directly to the probe. so there's basically no load on there except 100 Meg Let's try that again. All right, one more time for the dummies. Here we go.

Bingo, there it is. and our meter down here I'll turn that off and be careful, he's showing a hundred Meg So that's it's nominating that's nominal input impedance. so it's being on and you can see that we've got two affiliate what are we at? Twenty milliseconds per division, so it takes you know, 60 70 milliseconds to ramp up and switch on here. So obviously it's doing.

it's not made I can't remember the teardown which I'll link in down below. It's obviously not like ramping up and then like using a relay to switch it on. it's actually ramping up the output it would have been. That's not really what I wanted.

unfortunately I wanted it to build up the the high voltage to the capacitor bank and then when you press the test button to boom discharge. and that's not the input capacitance of the probe either because the input capacitance is only one Pico Farad's so you know it's bugger all. so that's going to have bugger-all effect on the rampion up there. So if we just go in here, it's going to never have a squiz.

You can actually see all the switching noise on there, which you expect. You know which is fine for an IR meter. You know that you know it is what it is basically. But yeah, there you go.

It is actually significantly above the five kilovolts though according to this I mean one, two, three, four five. It's like, geez, you know it's like at least five and a half. 5.7 kilovolts, Something like that. Alright, so let's try that again.

but let's hook up the meter this time. So I've got the probes hooked up to there and then the well, the output of the Iatest hooked up to there and then the high voltage probe in parallel with that. So let's give that a bill. and I have actually tested this before I Know that the Be M23 five does Actually I survived this, but I didn't have a scope probe to actually do it.

So here we go with single-shot CAPTCHA and test five kilovolts. Boom. There we go. Aha, we've got some clamp in.

Look at that. No overshoot whatsoever. Bummer, because that's really what I wanted. Oh So if we actually have a look at that, you can see it ramped up and then do some funny business.

Anyway, you can see the internal oscillation in there too the switching converter, but there is no. There is no overshoot there whatsoever. And we're on 500 volts per division. So 500 A thousand Fifteen hundred.

About 1,800 volts. It's obviously being clamped by the meter there because the output of the insulation resistance tester should be capable of more than that. But yeah, I was hoping to get like as a 5 kilo volts and then BOOM You know it. But these things clamp ridiculously quickly.

But the whole idea. the mobs inside the meter do. But the whole idea was that I was hoping that it would charge up because the capacitor banking side and then BOOM dump the energy. So I can't remember what the deal is there.

but yeah it's We've just got this slow ramp up so that's it's. no good anyway. Umm the fact is the meter does survive so still okay. But yeah it's not the it's not the big surge overload thing that I wanted because if you look at the proper test waveforms the impulse waveforms for the for the cat testing on ammeter then they actually have a specific response over X number of microseconds and stuff.

This is nothing like that. I Did you know it's just very crude attempt at you know potentially doing it as a like a go note. go no-go test for you know meters to see if they survive. And in case you're wondering, yes in UI 121 GW Eevblog meter coming out recently soonish.

Anyway, it also has survived but I haven't captured the waveform yet. so let's do exactly the same again. So this was the be existing waveform for the BM 2, 3, 5. so expect a similar sort of clamp in the inside the 121 GW or any multimeter with up mods for that matter that will lie clamp it down so let's have a look and test.

Boom Oh look at that. that's interesting Wow Look, that's the 121 Gr. you just beeping to the overload condition. You can see it a little display there.

so I'll turn that off and wow that it's jumped back down and has jumped up again. So it's kind of like a more severe test. I Guess let me let me take that out. Let me take the scale out a bit and we'll We'll redo, that, shall we? Let's give that a squiz.

No Okay, it's fine. So what's going on there? We got some sort of intermittent thing anyway. it is clamping a very similar voltage and a very similar way to the BM 235, which is exactly what you'd expect and the meter survives just fine. But that's really yeah.

Why did we get that weird waveform here? We have some. oh I Remember, there's a big high voltage relay in the output of this thing if you look at the teardown and maybe that's maybe that had some contact bounce or something. But anyway, that's really quite strange. We didn't see that again.

Weird. Anyway, what we've got now is the poster child for cheap meters these days. The painting an8 Double-o 8 and I have tested this and it did actually survive that this something before I got the probe, but there is something interesting that happens to it. so let's actually do this.

Okay, so five kilovolts exactly the same. Let's go and let's test it. Wow look at that and I'm not sure if you can hear that but that is arcing over inside. It is hideous.

It is absolutely hideous. but look at what was jumped up to unbelieving to turn them off before it dies in the ass. I It is obviously continuing to arc over there. just arcomage and you actually that manifests itself as a high frequency noise inside that thing.

I'll see if I can capture the noise. Alright, let's try it again. Five Thousand Volts got the external mic Oh meter just turned off and died. This is not good.

We've got some segments frozen on here and it doesn't seem to do anything. Have we killed it as some like back EMF into this thing killed it or something? I don't know. I've done this several times and it wasn't a problem. Damn might have killed it.

No, we're actually good to go. We're back in action so let's try that again. Just took the batteries out. just ludie soft button crap.

Anyway, try it again. Oh wow. Yeah, we killed. we killed it.

Stop. II Stopped. Oh no. it seems to be still working or going to check the cow, but it seems to be doing the business.

Let's open it up and have a look Anyway, on the aiming. We are actually getting up to like three thousand volts. So one thousand, Two thousand. actually three and a half thousand volts in that initial climb and then about.

you know one two. Alright, you know three thousand volt. Peaks on there. So yeah, we could survive that.

That's not bad. So I don't actually expect to see anything on the topside here. I Think it's knocking over in the range contact switches and I've done a video on this demonstrating this beautifully and I'll link it in at the end and check it out because it's absolutely brilliant. All right.

So let's try that again. Five Kilovolts. Here we go. It sounds horrible now.

Unfortunately, we can't power this up with the cover on because then the range switch and has the contacts and it will cover up everything else. I'm going to have to run up with it off I Remember this meter does not have anymore protection so it's not doing any clamping so the clamping is somewhere else in diodes or whatever. It does have one PTC in there which looking limit the inrush current but it's not doing any voltage. Clap in.

Anyway, let's do the five Kilovolts again and see if we can get some I can across those switches. Whoo there it is That's a 4.0 You can actually see some of the burn pit marks in there from where it's iced over. Anyway, let's try it again. This is going to be great watch.

Ah so as you can see the little aiming aw8 actually I survived that just fine in quote marks. Um, but don't go saying oh, look this fantastic. This $25.00 meter you know, like survives that you know, these three and a half kilo volt pulses. These you know horrible pulses up here I Know it is.

Yeah, it does, but it's that's not the point of the cat ratings and everything else. The meter that we've got here of what I thought this might be able to do is to charge up as capacitor bank inside and then dump the energy impulse it into the meter us hoping it would do that but basically all we've got is just to basically just a high-voltage power supply generator which then just some clamps internally in meters like in good meters like the BM 2, 3, 5 in the 121, GW that actually have the moles inside the metal oxide varistors that do the clamping or gas discharge tubes and other meters like our Gossin that used GD T's similar sort of thing. So in these meters just saw that it actually safely clamped the voltage. So then the PTC s and other input protection resistors and other diode clamping can do their job.

The aiming actually doesn't have that doesn't have any mods in it. it's just got the PTC So it's not surviving through good engineering where something like the B this is surviving through proper engineering, proper independent Ul, certification testing, and everything else. Right, it's designed. Those mods are doing their job clamping it down so that then the PTC's that come afterwards can protect the device and the input divider resistors.

Yeah, this thing did survive this, but eggs, No, it doesn't make it a good meter. it's got no more protection so we were just. you know, it's actually not that hard to protect against just a simple high voltage with input protection resistors and stuff like they don't necessarily need clamping mods just to do that. but the whole point is to dissipate energy.

This has no ability to dissipate, dissipate, high voltage, overload impulse energy whereas something with mods that's safe and designed to do it does. so this is not a good test for that. But anyway, I Just wanted to have a play around and see the unity meter. It didn't quite do what I want, but that was fascinating.

We found a fascinating result with an unmold protected meter and you saw that the other ones you know were clamping nicely at the 1800 volt level because these normally have like you know they might have like to 900 volt mods in series or whatever and then they clamp at the at the 1,800 volts or whatever particular rated mods that you have inside these things. but that's typical other to kilovolts and then the rest of the input protection can do its job easily and safely. The molds are designed to dissipate the energy so there you go I hope you found their interest. If you did, please give it a big thumbs up for engagement and as always, comment down below and I'll link in those videos at the end here.

Check it out! The Ted out of this was pretty interesting. It's not a bad, it's got quirky software II you know lockup issues which are seen here and in other videos, but you know five kilovolt insulation tester. It's not too shabby and thanks Charles at Trio Test for loaning in this high voltage probe. I'll link it in down below it's a couple hundred bucks and I'll also link in my which I haven't done a teardown of yet my Hv P 70 probe and there'll be a discount code down below and that one, but I got to do a video on that.

So if you're looking for a a professional ul listed probiotic, do this video just to plug these bits here. So why not? Yeah, I Haven't really advertised this yet, but quite a lot of people have I bought it already. In fact, my first shipment is almost done sold out. so there you go I link it in down below.

that's for safe high voltage differential probe measurement on mains type stuff. So different to what we are doing here. really. Anyway, catch you next time you.

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