Let's take a look inside a UVC sterilizing adapter that you plug into your phone and it sterilizes everything in the vicinity. To be quite blunt, it doesn't No, but it is apparently putting out UVC but not much of it. now. the only way I could find to hook this up was with a little adapter on it just to make it easier to hold and I plug it in here.

and if I plug this into the side here, it means the current is not going to be going through this measurement device but I have measured it by other means and if I plug it into a USB power bank, this will display zero but it is now lit and I've measured the current at just 30 milliamps which seems very low given that this is supposed to be fairly high power ultraviolet LED and it's got the visible LED next to it. if I bring in the UVC test card and let's Zoom down in this, let's Zoom down a little bit if I bring it in and hold it over the darker darkening UV UVA but it does show that it's putting out the UVA or near UV it's that Violet LED and I'll show you that I close off the LED in a moment. but when I put it near the UVC sensor I don't even know if you yeah you are seeing it you can see that there is something going out there. It is putting out a little splash of the UVC enough to make the force for glow but not really enough to do much else.

Certainly the impression they give is that you can simply scan it over your bench and it sterilizes it. It's not going to do that because uh, it's really low output. nothing compared to I'm not even bothered having this pointing at me. it's that low.

Nothing compared to for instance, a classic little inverter which is bulkier to be fair. and the mercury vapor tube. These little quartz mercury vapor tubes that put out tons of ultraviolet. Let's unplug this.

I Also have glasses on that protects my eyes from your VC as well because I've tested them and they do not pass. UVC Let's put this to the side and then we'll get the spudger in and we shall open this. I am now looking for the spudger of where is my spudger I shall try stuffing my fingernails down in the meantime. Well actually you know what that is kind of working that is kind of working fingernails to the rescue I Could just look for the spudger but I have kind of misplaced it.

Oh no, it's popped open there we go now. before I even look at this. the low current makes me think they've just used it. Resistors in the series two resistors.

Is it? No, They actually have circuitry, right? Tell you what. I'm going to take a picture of this and we'll reverse engineer it and see what it's got going for it. One moment. please, let's explore and we'll start with the UVC LED on its own because it's quite an unusual device.

It has a strange package because the UVC chip is very destructive in its output the UVC wavelength and it can't pass through resin or plastic. You have to use a special glass or quartz, so they have a metal package usually this brass color I Don't know what the material is, maybe it is brass, but in that they have laid in a little sort of quartz window. underneath is a UVA chip for visual effect and also to indicate when it's on, but to give that people that reassuring it's purple and therefore it must be putting out UV type of thing. There's the dodgy UVC chip and in parallel with it is a protection component, possibly just a diode.

It certainly measured as a diode and that is presumably to protect this against reverse voltage. If we take a look at the circuit board, the back of the circuit board isn't that exciting. It has a very large ground plane. It's got the USB connector with the shell connect to negative, the positive connections are reinforced and then it's got one connection going over to the UV a LED and one going over to the UVC LED.

There is the facility for other LEDs in this that they haven't used, possibly to allow for a cheaper package. I shall show you that in a moment. So here's the incoming connector. There is a resistor connecting to one of the control pins and it fills to the zero volt rail.

There are four decoupling capacitors, one big one, three smaller ones. Not sure the fires are because they are in circuit. There is a three volt regulator and the three volt regulator is purely for the UVA led to provide a stable voltage. They could have just used a resistor for that.

I'm not sure why they did this. Strange. There are lots of quirks in this circuit board. If they had decided just to use a couple of UVA LEDs in parallel, there's a resistor here across the five volt that could have made that of obsolete and then they could have just used a simpler UVC LED with no ultraviolet chip in it.

I'm not sure what these are for, Maybe they were just wanting to Beef It Up and make it look brighter. There's a lot of theater goes on in germicidal sterilization, pandemic type stuff. There is another section here and it's this now because the UVC trip requires a fairly high voltage. it's got a voltage roughly about five volts they've provided.

maybe just over that because as the wavelengths gets shorter, the voltage across LED is higher. This is why Red LEDs have a voltage of two volts and the blue at the other end of the spectrum have a voltage of three volts and as you go through the ultraviolet Spectrum it just the voltage gets higher and higher across the LED. So they've got a boost circuit based on this b6297c which equated to another chip, a little Schottky diode, an inductor to boost it up, and then this circuitry here is a six volt Supply set by these um, feedback resistors at divider Network and then a 56 Ohm resistor and I measured the current at 8 milliamp through the UVA LED from this circuitry. With that 5.1 ohm resistor in series and 17 milliamps through the UVC LED which was quite low I was expecting to be harmed that I'm not really sure what these chips are rated.

Let's take a look at the schematic. Anything else worth mentioning here? No lots of capacitors. Oh, couple of resistors. Here is a divider Network for the enable pin, but I'm not sure why the data sheet for the Mt3608, which this it closely equates to, Well, it is pin compatible.

The data sheet for that suggestion basically just tie it to positive to enable it and tied to negative if you wish to disable it, but they've used a voltage divider. But anyway, the USB Supply comes in. there's four capacitors. There's also that resistor going to the zero volt rail to e control pin, presumably just to say there's a load connected out current on the USB port of your phone, there's the three volt regulator with its own little decoupling capacitor 5.6 Ohm resistor, and the UVA LED there's a boost circuit with its inductor, the Boost circuit when it's enabled, which is all the time by this divider here, which is kind of not needed.

They could have just tied that across. It pulses at about 1.2 megahertz if it isn't an Mt3608, and each time it pulses to the zero volt reel. It puts a magnetic field into this and then when it turns off, the field collapses and the higher voltage Spike goes through this. Um, I was going to say zener down, that's not Schottky Diode and it charges up this cluster of capacitors.

And they've got a cluster of three capacitors uh, two acting I mean Reservoir capacitors probably in one smaller one just to for the law, impinge, just to basically catch that very high frequency pulsing current. The voltage is monitored by the feedback input, which has a voltage threshold of 0.6 volts. So by choosing these resistors to match I think this one's roughly 10K. That's roughly 100K ish.

but it gives a a 6 volt. So technically speaking, that would be more like 90k and 10K. But uh, very hard to measure in circuit because there are capacitors and stuff in the vicinity and other circuitry. Then it goes through the 56 Ohm resistor, that stable voltage and drives the UVC LED and it's got the reverse voltage diode across.

That just a measures as a standard diode, not a shortcut key diode, that is it. So quite complex. Really, you would have thought they could have done it simpler. but I guess the biggest problem is the fact the UVC LED does require that higher voltage um then standard 5 volt Supply But certainly this bit could have been so much simpler.

they could have got rid of these. They could have basically got rid of that um, but uh, they didn't. They just kind of just over embellished it. But that's it.

That's how your useless low output waiver over your table as much as you want. It's not going to sterilize anything. UVC USB dongle thing works. It's intriguing.

The one good thing about these is that the pandemic caused a massive surge of demand for ultraviolet devices. So the company's manufacturing standard UVC tubes and the little quartz ones like this have just been lapping that up. They've been getting lots of business and uh, it pretty much established the market for the UAV UVC LEDs. And the one place these do have a major advantage is if you have a medical piece of medical equipment that needs a tiny little area sterilized, then this is probably okay for that.

I Believe they're also use them in some water bottles where they just rely on a sort of long-term exposure from it. but um, I'm not sure you determine just the consistency of how much UVC you're getting I don't know how fast these degrade, but that is it. The tiny little UVC USB dongle.