In today's episode of things from china that can hurt you in unexpected ways. We have an ultraviolet germicidal lamp, but you might be thinking that the harmful bit that's going to hurt. You is the uvc energy from it, but in reality i'm not sure. What's going to hurt worse well, that is going to hurt quite a lot, but the fact it can also maintain a charge with a big fat capacitor inside of up to 300 volts or more across these contacts when you unplug, it is also a potential source of Surprises, let's plug it in so i'm going to bring up the hoppy, the pink socket, because that is going to make it safer.

Obviously, here is the hoppy tester and i shall plug it in, and i shall plug this in here and when i plug it in. I want to point out uh: i will be exposing myself to some level of uvc radiation - i'm not too concerned about that. It's going to be a brief exposure er, but watch what happens from this light. Let's zoom down a bit just so you can see what happens when it lights now, put it at a nice.

Comfortable height watch this of discharge inside here. So what you saw there was the filaments glowed briefly and then the ultraviolet charge ultraviolet discharge start occurring got to keep my fingers away from that. I'm going to point it away from me because uh looking at that is not a good idea. The power is quite low, it's 2.5 watts, which is actually under run the lamp in a way which is good uh.

The current is 0.3 amps, 322 milliamps at 244 volts and the power factor is an absolutely appalling point: zero three uh power factor so that uh kind of uh gives a clue as to the circuitry inside this. So i'm gon na unplug this uh before uh. I get i get nasty experiences the lamp here can potentially put out to i'm gon na have to be careful here. In fact, you know what, before we go any further, let's bring the meter in.

Let's set it to, let's set it to a thousand volts, because well, let's be optimistic about this and we'll see depending when you unplug in the sine wave, it will potentially hold a voltage across these pins. I can touch it under that one um only 145 volts. That's all right, let's say i give it another blast unplug it again see if we can get a higher voltage, because it does depend when it does in the same wave still about 140 volts every time you unplug it. It will be a random voltage, 329 volts.

So that would definitely give you a bit of a zap and uh if i short that out, the screwdriver you'll hear that it's available quite a bit of current thanks to the uh gas discharge, uh shunting it here. So if i just basically get a screwdriver and short that listen, did you hear the pop? Did you see the little flash? That's not something you want to get your fingers onto. That would hurt. That would hurt a lot.

It's a big capacitor right, let's open it up and take a look inside while i explain the signs of how that lamp works and how they're ballasting it cheaply. I think this came from banggood uh. I was hoping it was going to have a fancy electronic ballast in the side. No, it's not.

It's got capacitor, so these lamps and it's worth mentioning uh. Oh that's another test! I'll! Do it's worth mentioning! You shouldn't really finger these lamps. It's not going to harm! You well unless it's on at the time, but it leaves greasy fingerprints and, in the case of quartz halogen lamps, the tungsten halogen lamps, those greasy fingerprints cause a buildup of heat and it causes de-vitrification of the quartz. In the case of these lamps, it's different.

If you put your fingers on the surface, but you don't wipe it down with isopropyl alcohol afterwards, it will potentially inhibit the output of the certain wavelengths that ultraviolet light, because these lamps can put out theoretically two wavelengths. You get different versions. You get the one with ozone and the one without ozone, the one with ozone puts out. It's got a very transmissive, quartz or uvl glass, which can transmit the 254 nanometer wavelength, which is uvc and it's the stuff.

That's it's used for germicidal purposes. Basically speaking, it kills anything in the vicinity of the light, uh and causes. If, if you held it against your skin for any long period of time, it would probably cause blistering in the skin if you looked at it with your naked eyes, uh, because, unfortunately, it's very alluring, it's a lovely colour. You would potentially wake up the middle of the night with arc flash you'd feel like there was sand in your eyes very unpleasant.

It does pass it's not a permanent thing. It passes in a day or two, but the other wavelengths that you can get out. Some of these lamps is 184 nanometer and you'll know. You've got one of those because you'll get that distinctive bleachy smell of ozone off it, and that has proved to be very tricky.

Let me just go and grab some some of these lamps one moment. Please a box of the lamps and some holders. I found it very hard getting the exact size of holders for these. I wanted to make the world's worst pair of worst set of christmas lights, the ones that can actually hurt you again.

It's the german side of christmas lights, a great idea. I tried so hard to get the ozone ones from the listing. The ones marked 03 are ozone. This is not ozone, not ozone.

It was a lucky dip. The ones i bought that claimed to be ozone uh were mostly not so it was. It was almost a pleasant surprise to actually get one that was on his own. I'd bought loads of these just in a desperate attempt to find to find well yeah less than half of them generated the ozone.

These were all supposed to be the ozone generating lamps. It's kind of interesting, the way the ozone layer works. It's continually splitting oxygen to separate atoms of oxygen, the recombined ozone and then the other wavelength of ultraviolet, then recombines them so they're, always up changing between oxygen and ozone. That's actually what these little lamps do.

The ones are o3 they're, not super efficient at generating ozone, because they're also breaking down as at the same time as they're making it, but they generate a little bit uh. But one thing i want to test here: let's screw it part the way in, let's make sure that's discharged. Yes, that's fine! I think it's discharged yeah, no nasty surprises for me just out of interest have they followed the normal thing where the outer ring here should be connected to the outer ring. Here, that's no good! Unless it's through capacitor.

No, it's not the uh. The outer ring of this holder is actually connected to the tip of this. That's naughty, because it means that as you're screwing it in you could actually get shot. But, to be honest, you wouldn't be screwing into this anyway.

You wouldn't be touching this because uh the ultraviolet light is very destructive. Breaks apart. Everything right tell you what let's get this lamp out and grab a screwdriver. I shall grab a proper screwdriver for this just to make it look like a professional and we'll take this apart and i'll show you the circuitry inside, which is, i will say, just a little bit disappointing.

It's not what i wanted, but that's, okay. It is what it is when you buy stuff in the gray market, you get what you get. Oh, the dreadful purr factor uh, because the power factor is absolutely dreadful: uh, it sees a high apparent power. So although this was only measured about two and a half to three watts, it would appear to the electrical distribution industry as 80 watts, just because it uses phase shift.

That is a big. I thought that was just a trim. It's a while, since i i took this apart when i first got it, i've made so many videos about these things. The you know, germicidal lamps, that i felt a bit awkward at the time i could put it put it on as little hiatus uh.

There is a bracket in here for the lamp well, that'll also explain why it was at an angle. There is only one screw holding this in it's designed to take two screws. I can fix that uh there's the capacitor, which is that, oh, that's, not good. I'll.

Tell you what uh, let me see that let me just uh pop this little cap off and hopefully that's where that came from. Otherwise, i'm gon na have to use deep probing with a soldier iron to get this back into action again. No, that is trapped around the room. That's all right! I can fix that right say what that means.

I can measure this capacitor. I just ping that little stun i haven't the clue where it went uh. I can measure the capacitor by bringing the meter in setting it to optimistically 200 mega fart. I really don't know what it's going to be.

I'm always a bit coy about using capacitive, droppers and capacitive limiters. It's basically just pasture and sears the lamp. It's got a tungsten filament, but it's also got the glow discharge. I'll show you that afterwards, i'll do a little doodle a little sketch.

So here is the capacitor. The capacitor is going to. This connection is quite high value, capacitor, it's 3.9 microfarad. That is really quite high hold on.

I see that in there yeah get the right button. Here is 4.2 microfarad, 400 volt ew spicy right. Tell you what i'm going to do a little doodle now and show how these lamps work one moment please. So here's a very simple schematic: all the work is done by the lamp.

The capacitor allows a certain amount of current to flow in each half cycle and in the case of the lamp itself it has a filament. Now the lamp is only rated for about 10 volts. These things were originally used in things like tumble jars for sterilizing, your laundry they'd be in the air path. There'd be a transformer that put out a fairly high voltage.

It has to be a slightly higher voltage. Initially and they'd normally use a resistor to ballast it. This is a bit cheeky actually using capacitor. It's a bit over minimalist, i'm not sure if it's going to impact the life of the lamp because uh the capacitor can actually let through quite high current spikes, but the lamp has a filament in it and at the ends of the filament, it's got a coating, A thermally, emissive coating and if you look at the lamp itself, if i get a bit of black card to show you this, is this going to be relatively visible? If i do this, if you zoom down, can you see that sort of white coating at the end of the filaments there? That is a thermally, massive coating that when the lamp is hot, it starts emitting electrons i'll, just zoom back in this, because i didn't mean to zoom out quite so far uh.

So when you initially power it up, the filament heats up and it starts emitting electrons. It breaks down this voltage required to couple to this, which is the mercury vapor inside now. If you actually look at the lamb itself, it's got the there's no glass support in here, and it's got the two electrodes with a v-shaped filament. The middle connection is purely for support.

The uh, the two outer ones, the main connections and the the coating is at the top here. But at the back of that i thought it was a getter at first. I don't think it is there's a little metal plate. Also just sat at the back with a textured surface and it's supported by a little other little stem coming into the glass and it may be uh amalgam material that actually, once this filament heats it up.

It releases the mercury vapor and that's going to burn out by the slight hint of a mercury vapor in the back of this. But the main point of this is that it makes it means that, instead of having a fancy circuit and a high voltage whatever like a fluorescent fitting, it means they can just run this at low voltage, low power and the filament provides the heat. And some of the ballasting effect, but also it uh - does the sort of coupling of the the mercury vapor the mercury vapor once it conducts actually sort of dominates that shunts the it forms a conductive path across that i made a video about these um. So that's.

Why you need a ballasting series? If you didn't uh, it would potentially cause problems. That's why the capacitor is a bit naughty, because you may have noticed the filament, the globe, jiggling batteries and forwards, it's kind of re-striking in every half cycle and alternating between the two electrodes, but with the capacitor, that's going to cause a little current spike each time. I would expect these to go black around the outside, but i've never really tested for a long length of time, but that is a it. It puts out the uvc.

The uvc is that destructive wavelength that sterilizes stuff in its vicinity - and that is its purpose. This is a chunk of aluminium with a plastic insert, i mean otherwise, it seems quite nicely made. I would guess this was probably an led lamp in a previous incarnation like it's specifically designed for this application, but it looks like a universal case that they've just stuffed the capacitor into in the lamp holder for this. But that's what a lot of companies did at the beginning of the pandemic, which we're just getting to the end of at the moment, hopefully uh, and they just cashed in the hysteria and ebdy wanted to sterilize everything with ultraviolet.

This is one of the products that came out. So if you get one of these two things to note, don't look at the light. Uh always make sure it's in an enclosed area where you can't either expose skin or your eyes to it. That includes pets and children.

Another thing is to remember that, because they just didn't add a capacitor across this. A resistor should say across this capacitor a one mega, ohm discharge, resistor uh would have just done the job. It means that when you unscrew it from a lamp holder, it could potentially hold quite a charge in that could give you a good nasty zap, but an interesting thing. Nonetheless, there is a video uh dedicated to the gtl3 lamp uh.

It's quite interesting and the ways i tried driving it but uh. This is the first time i've used the capacitor. So i'm guessing that in lower voltage countries 120 volts countries, they may have a higher value capacitor or they may just use different circuitry. I'm not really sure i don't even know if it's available for 120 volt, but that's it.

It's an interesting thing. It's certainly novel if just a little bit freaky.