Testing UVC lamps with a cheap UVA/UVB sensor.

[@andyhill242]

I think this is a reasonable test, Clive. Without going to great expense, I think you have proven the fakery of these products.

[@jethrotull5847]

Thanks Clive, When I fist saw the bandwidth on the detector I said “what is that going to prove ?” The addition of the glass as a UVC blocking filter was genius ! Well played Sir !

[@Berkeloid0]

Excellent test! What a great way to demonstrate it. Also great to know for those of us wanting a quick test without buying a sensor, we can just shine it on something that fluoresces under UV-A light and expect no fluorescence with the light under test, if it is supposed to emit only UV-C.

[@mydickissmallbut9716]

UV-c does cause fluorescence though...

[@Berkeloid0]

Maybe you should look at the video where he demonstrates that UV-C doesn't cause fluorescence.

[@mydickissmallbut9716]

@@Berkeloid0 he demonstrated it causing LESS fluorescence. I suspect that a large factor in that is the brightness of the source. Anyway, without a reference it would be hard to judge if it is just dim uva or true (maybe dim) uvc.

[@Berkeloid0]

Yes but it's so little fluorescence it may as well be none, and will make a great quick test to see whether you're looking at a UV-A or UV-C source. Of course you'd take the relative brightness into account, nobody is saying you're compare that disco light to a single LED. And if you're talking about reference sources then I think you're going a bit beyond a quick test...

[@Berkeloid0]

@@johncoops6897 That's very true, but if you bought a UV-C LED and 90% of its light output was in the UV-A spectrum, I'd be wanting a refund given how much cheaper UV-A LEDs are!

[@AlanW]

I'd like to see an actual UVC LED tested with this method!

[@Muonium1]

the sensor on this device is also by definition an LED so you could just buy another one and run it in reverse to test.

[@LittleRainGames]

@@Muonium1 thats first thing i noticed in the thumbnail. I actually think i have the same ones

[@bigclivedotcom]

Coming soon, by which I mean hopefully being delivered from China soon.

[@penfold7800]

@@bigclivedotcom well ebay has deffinately removed its restriction on recieving goods from china (before it wouldnt even let me pay at checkout) cos i have received two items from china this week. they are masks which ive soaked in disinfectant and washed in antibac dish soap. what i dont know however, is whether its safe to use the 'filters' that came with it cos i dont know whats in them or how to sterilize them (im hoping the black stuff in them isnt radioactive carbon)?

[@rpavlik1]

@@penfold7800 it probably took at least a week to get to you, right? Then as long as you disposed of the packaging properly, the stuff inside is already safe. Time is a disinfectant against most (not all, but most, including our current foe) baddies. Masks can help, they just aren't perfect, and they wanted to save them for health care workers, to compensate for being unprepared.

[@imranahmad2733]

UV LED torches also make all the segments on a VFD display glow, also old monochrome CRT oscilloscope screens glow aswell.

[@spvillano]

@Mai Mariarti you might not want to shine one in a five star hotel either. Do you honestly think that they scrub the walls, shampoo the carpets and change the bed cover every day?

[@TheJunky228]

Well, those are both phosphors as well, right?

[@vmelkon]

@@TheJunky228 Yes, it is normal that they glow. I have a CRT PC screen and it glows green under disco UV lamp.

[@imranahmad2733]

@@vmelkon I have an old Compaq V50 CRT monitor and that gives a whitish glow, but my agilent and iwatsu scope gives a green after glow with trails.

[@captgary278]

@Mai Mariarti lol, so true!

[@markpinther9296]

I just want to express my gratitude for all that you do. With what you provided about this UV sensor etc I was able to test two of my corncob lamps from two vendors and they both had zero output of UVC when using glass/no glass. I so enjoy your work and channel! First started listening back when your mother was suffering from Alzheimer’s and you provided a lot of personal insight that was helpful to us with parents in the same boat.

[@Thirdbase9]

That first UVC light was scary.

[@robertpryor7225]

Pretty sure i baconed my retinas just watching on phone

[@2100BLF]

The most powerful chinese models on Aliexpress/Taobao/Tmall are 100W and 150W. 68 to 88 cm tall models. PL-L style tubes.

[@buddyclem7328]

@@robertpryor7225 Bacon can be a verb now? Awesome!

[@buddyclem7328]

@starshipeleven #BraveEnough

[@nicam49]

@starshipeleven Yeah! just look at 'medal' and 'medalled'

[@GRBtutorials]

This is exactly what I was intending to do to test my UVC lamps! I read about it online, so I decided to buy this sensor. There’s actually a UVC variant of this sensor (instead of “GUVA” it’s “GUVC”) with isn’t that expensive (around $9) sold on DigiKey, Mouser... And try some real UVC LEDs next, I want to see how much it detects compared to the mercury vapor lamps.

[@millomweb]

Surely all you need for us amateurs is a light sensor (PV/LDR etc.) that works with UVC, a piece of glass and a dark room ?

[@DejanGjorgjevikj]

GUVC-T21GH, trough hole, with amplifier, voltage readout, slightly more expensive thou @ DigiKey, ISweek, ROITHNER LASERTECHNIK GmbH, ...

[@GRBtutorials]

pmailkeey Yeah, interestingly enough, LDRs seem to have some response in UVA (couldn’t find anything on UVC, though). If you had something that blocked visible/UVA but not UVC, it’d be possible to see if they do indeed detect it... Silicon PV cells seem to detect down to 300 nm (so a bit of UVB), but no UVC, and same with regular photodiodes.

[@millomweb]

@@GRBtutorials So LDR with known UVC source in dark room & a piece of glass to filter out UVC and see if LDR value changes. If it does, it's responsive to UVC.

[@GRBtutorials]

pmailkeey Oops, didn’t think of that. Regular soda lime glass also blocks UVB, though. Borosilicate glass (Pyrex), or maybe some other material would probably be better for that.

[@kardeef33317]

Great video Clive, you should send that seller and Ebay a link or copy of this video. On another note, I thought I knew a lot about UBA , UVB and UBC and yet again I learned a lot from one of your videos. Thanks Clive.

[@eveyoung3656]

I’m pretty sure those Chinese seller don’t worry too much about false advertising.

[@tanbirulquadirchoudhury4818]

I had tried using UVM 30A, made for UV index measurement and is doing a good job with Arduino. I had actually wanted that to detect UVC. The sensitivity in the UVC range was low , however i just wanted to detect rather than measure. No response (mv generated ) whatsoever. If you or any of your readers have any experience. The GUVA S12SD is not available here, the reason why I decided to use UVM 30A Thanks for your effort. With a demonstration like yours, things get a whole lot clear.

[@PghFlip]

Good test as I've come to expect from you... Interesting to see the difference between the first lamp 1V vrs all the others in the mV range. Hope you're going to send this to the sales lady who tried to call you out...

[@satyris410]

I'm sure Mary would be very apologetic but still insist you were wrong and she was right.

[@PghFlip]

@@satyris410 :D :D

[@witeshade]

My favorite blue glow is the glass of a higher power vacuum tube, like a 6L6 or 6550, which glow blue when the stray electrons that missed the plate hit the glass. Its a really satisfying color and it usually reacts to the audio signal as well.

[@urugulu1656]

or the startup of a nuclear reactor...

[@albanana683]

My VTL monoblocs each have 8x 6550s. Very satisfying, but the Russian tubes I have now are not quite as good as the original GEs.

[@johnjordan3126]

Gratifyingly scienticious. :-) Ozone detection is another confirmation point. Aside from the sniff test, I found cheap (< US$10) ozone test strips on Grainger. I use GTL3 bulbs in a Styrofoam cooler so I get a good whiff of O3 after a sanitizing run - which you informed me was bad for my lungs. So much for the "April Showers" freshness.

[@bigclivedotcom]

Brief bursts of ozone are OK. The main hazard is continuous long term exposure.

[@Milamberinx]

I think the UVC LEDs don't produce much ozone so that wouldn't do much to prove the fake germicidal lamps are fake. Maybe it could help with the test of the effectiveness of the tubes though?

[@jfan4reva]

@@bigclivedotcom This explains why the entire population of the middle part of the U.S. doesn't drop dead every summer (thunder storm/lightning/ozone season.)

[@buddyclem7328]

@@jfan4reva You don't hear about subway workers getting sick either. I love the ozone smell of high voltage.

[@waltp3373]

Thunderstorms produce ionized air freshness. Ozone produces dangerous air. There's a difference.

[@esunayg]

I was trying to figure out an easy & cheap way to do the same, I also know regular glass blocks uvc, but never been able to combine those informations :) youre genius! impressed!

[@nutsnproud6932]

That mechanics light (the one you recently took apart) is often used to detect leaks in Air conditioning. Mechanics put a UV dye in the air con system. If there is a leak the dye shines when a UV light shines on it. I hope that helps.

[@NY411Info]

Yeah I commented on that video he did that the light looks like a Chinese copy of the Astro light that Eric O uses on SMA.

[@JerryEricsson]

Thanks for the great info. I think I have a UV tester in my arduino collection, I purchased it years ago when I started planning my tricorder project that got sidelined never to be seen again a couple years back. I think I will dig it out and see what she says. I do have a bunch of UV LED'S that I picked up for their black light glow light, then after seeing your video on the dangerous UVC light, I did buy one of those. I used it once in my shop, and my eyes were screwed up for three weeks. I should have heeded your warning, but thought a couple quick looks shouldn't hurt, after all I wear glasses, very thick glasses that the optometrist said had UV protection built in. You know your videos are sort of like a visit from an old friend, always welcome and usually way to short, but comforting none the less.

[@reddragon27284]

There’s an ad for the UVC light you showed a few videos back next to your video with the title “Reduce the chance to get sick”. I wonder how many people buy real uvc lamps not knowing the danger.

[@CoolJosh3k]

RedDragonUKTech Well there are more than a few Trump supporters, so...

[@dogphlap6749]

You can "reduce the chance to get sick" by spending time outside in daylight (the UVB you will get kills COVID-19 on surfaces (obviously not in vivo)). In 1918 it was noted that soldiers in field hospitals (where they did spend time outside and had better ventilation all the time) had one third the death rate from influenza as those in traditional hospitals (yes I do know it was a different virus). Breathing re-circulated air like the stuff you breath on aircraft and cruise liners is a bad idea.

[@edwatts9890]

@@CoolJosh3k ...There might be enough to tell the progressives to avoid staring at the sun.

[@zakofrx]

@@CoolJosh3k begone with your TDS Troll....

[@Akula114]

Very good, Clive! You've probably saved a good number of people quite a lot of money and possibly protected the health of many who thought they were getting a real product rather than some useless purple bauble. Thanks!

[@nerdydev]

Does that power bank vibrate?

[@zebo-the-fat]

it will when he modifies it!

[@mushroomsamba82]

Lithium batteries shouldn't be take internally

[@non-human3072]

I was going to ask that too..

[@__-nd4hf]

Reminded me of AvE modifying Hitachi Magic Wand to make it wireless and possible to use as a powerbank

[@steviebboy69]

I was going to say it rather looks like a mini version of one, you woudnt want the Lithium Cell exploding in use either.

[@MrShwaggins]

Thank you Clive for this video. I'm glad you put this out. I was about to buy one of these UV lamps from Ebay and them I remembered how much luck you have with Ebay things. I sent you an email asking you about this and how to test the type of UV light and I'm glad others have as well

[@foogod4237]

It occurs to me you could probably make a pretty good UVC tester by using two of these modules, one bare and one covered by glass, and then feed them into a op-amp/comparator to output the difference of the two signals. (though I'd bet you could probably look around for a fairly cheap UVC pass filter to put in front of it too)

[@fitybux4664]

You'd make a UVB + UVC detector. (UVB is also blocked by glass. Wheee, there goes your Vitamin D from sitting inside a car / inside a house sunroom.)

[@brawler6216]

@@fitybux4664 Well fuck, that makes a sun-room less appealing... Can we make a glass that's better?

[@fitybux4664]

@@brawler6216 it costs like $20 for a 2 inch x 2 inch sized piece of glass that is transparent to UV. (Gallium arsenide or something.) Also, it would be very thin and fragile.

[@martincunningham3052]

Much needed information! I have been looking for this info for a while and have recently come to the same conclusions. It is incredible that it has taken this long for this to get out and it took someone on KZbin to do it

[@Yrouel86]

Pretty good test, it makes even more obvious the ebay scams. I would've liked to see also a comparison with an actual black light/Wood light (the tube kind not LED) but oh well you still made your point

[@markeccles3465]

How did you comment before the video was made?

[@Gengh13]

@@markeccles3465 are you telling me you have never met a DeLorean owner?

[@mikemondano3624]

It may be worth pointing out that it is not strictly an "Ebay" scam, but one by the sellers. _Caveat emptor._ Ebay can't realistically be expected to test every device on their site.

[@1amNick]

@@markeccles3465 He posts the videos early on patreon.

[@IDEBELAJAR12]

wuih

[@Weaponsandstuff93]

Pretty ingenious way of testing them, reminds me of connecting a basic ionisation chamber to a multi-meter to see if the radiation level fluctuates. No GM tubes needed etc

[@smartroadbiker]

Oo another thought, what other transparent objects block UVC :D i.e. polycarbonate (which I guess is what those lenses on the DISCO lamp are made of?)

[@taith2]

Pure acryllic does let some UVC trough, but most of sold acryllic have extra additives that often might block UVC. Sure way is to have quartz glass lens for it. Also existing UVC LED are probably worse in efficiency compared to traditional mercury. And they have abysmal power output. Only saving grace is longevity, however traditional lamp 8000h is nothing to sneeze at.

[@millomweb]

If it blocks then it's not transparent ;)

[@user-dj1hy6zc6q]

@@millomweb Don't you consider glass transparent? It blocks UVC. "Transparent" relates to the ability to SEE objects through it. UVC cannot be seen. Therefore it can be transparent and block UVC at the same time. Have you watched this video yet? This is kind of an important concept for the content of this video.

[@millomweb]

@@user-dj1hy6zc6q Not to UVC !

[@BedsitBob]

@@user-dj1hy6zc6q ""Transparent" relates to the ability to SEE objects through it." Depends on which definition you use. Second definition from Mirriam Websters Dictionary:- allowing the passage of a specified form of radiation (such as X-rays or ultraviolet light)

[@keithweilacher4890]

Good start. Disinfecting w/ UVc is also dependent on power (wattage, or specifically mJ/cm2). This is typically referred to as UV Intensity. So to kill a particular "bug" you have to give it the necessary "dose" which is Intensity x exposure time. Keep up the excellent videos.

[@mikeselectricstuff]

Many years ago when I was playing with an UVC eprom eraser lamp, I noticed that UVC produced a very noticeable afterglow on a strip on a UK postage stamp - not sure if this is the case on current stamps though , or whether it was a security feature or something to do with automatic recognition in the sorting equipment. At some point in the past, letters were printed with UV -sensitive dots to encode the address, again I don't know if this is still the case

[@mikeselectricstuff]

Might be worth trying UVC vs. UVB/A on various banknotes.

[@joinedupjon]

Hi mike - think it was automatic sorting based on an old 'how stuff works' type documentary I saw years ago. you've probably also noticed there's some pale orange dots look like they've been inkjetted onto the front of some window envelopes - those glow up nicely in UV as well - I guess it's encoding the postcode when OCR fails

[@bigclivedotcom]

I've tried the hand wand on notes and stamps and only got a glow from the same areas that light for UVA. The clear mercury tubes do have a strong violet peak.

[@dasy2k1]

One more test to do.... See if they will light up the security feature on a banknote..... That's supposed to light up in the UVA ranges towards the shorter wavelengths of it

[@peterarisz2150]

That powerbank though... a bit questionable?

[@wwsxa39]

Because it's not pink? ;-)

[@urugulu1656]

nope looks totally fine to me. just has a mold that makes it look sketchy when not paying terrible amounts of attention looks kinda like duct taped...

[@DirtyPlumbus]

Depends how you insert it.

[@BedsitBob]

Kinda looks like a 5V DC dildo. 😁

[@enterthekraken]

Yeah, doesn't have a flared base?

[@angrybeard1645]

1st of all I need to say thank you. What I have learned from you about UVC since the beginning I class as a public service and a benefit to all. I knew of UV lights etc but when the world become sick I started to research more, learning the effective wavelengths as well as the dangers early on was a massive help (from you). I have since purchased (from eBay) 2 lamps claiming to kill mites and help stop mould etc as well as produce O3 (they are the cathod tube style I think, def not LED) and was seriously thinking about the 100s of led lights claiming the same results. After looking up the UVC LED’s I was glad I didn’t but all the same you never know if you have missed some info while researching and that the LED may actually be new tech and work. Either way this test does more than settle my mind that I made a better choice as all the ones you have recently torn apart are the exact ones that flooded my screen searches as well as the gu10 fittings. Quick question, is there any way to check the claimed output wattage? I have an 8watt and 11watt but I’m not confident it’s correct or that it would effect enough area in a room. Thank you again from me and my family.

[@bigclivedotcom]

You can get plug-in power meters that analyse your appliances.

[@jkobain]

I can't wait to hear more about your dispute on eBay about that fake 'UV' disco lamp. And this test is what I expected from our Big Clive! ♥

[@extrastuff9463]

The one where a reply stated something about being able to see the purple light which was supposed to prove it is a real working UVC light?

[@jkobain]

@@extrastuff9463 yeah. This is already crazy as hell, although quite normal on eBay.

[@NY411Info]

Is he gonna do a dispute. I didn't hear about it. It would be nice to boot the scammers off of the Ebay site.

[@jkobain]

@@NY411Info find the video with that fake UV disco light, then move on to the next one, and you'll see for yourself.

[@blitzroehre1807]

Excellent demo, Mr. Clive! BTW, another surefire way to detect UVC is with Zinc silicate (Zn2SiO4), AKA Willemite in its natural mineral form. This phosphor was used in magic eye tubes and VFD displays amongst others. Under UVA light it hardly fluoresces, but under UVC light it glows bright green. I sometimes work on UVC sterilizing equipment and my quick and dirty UVC detector is an old burnt out magic eye with the glass bulb removed. Handy and needs no power :-) Probably easier to get hold of would be a surplus VFD display from a dead VCR or DVD player with the front glass cut away.

[@thomasr.6807]

Can you please test one of the "corn cob" uvc led lights? They are very bright and similar in color to the lighter blue but I am skeptical and would love to see the test. Thanks for your work.

[@bigclivedotcom]

I have one. It's fake. Just ice-blue LEDs. Note that the exposed solder connections on the lamp are referenced to the mains supply when powered.

[@penfold7800]

@@bigclivedotcom ooh, very dodgy then. not only fake, but shockingly dangerous too. brilliant!

[@steviebboy69]

@@bigclivedotcom So not only fake but you would be in for a rather shocking experience if you touch the solder connection and earth hehhe. Thanks for doing this to save us from being scammed.

[@IDEBELAJAR12]

wuih

[@agvulpine]

Do appreciate the UV-C series! Thanks for featuring these different products and knock-offs.

[@phonotical]

Have you seen the DIY spectrometer project? Uses a webcam loosely tied by calibrating known sources

[@mostlymessingabout]

That's only visible light

[@xorinzor]

@@mostlymessingabout generally they would be able to see infrared light too, although most of them just have a filter blocking it

[@Muonium1]

there are like a hundred of them, which one

[@mostlymessingabout]

@@xorinzorcameras can see visible light. Near IR if you remove the filter. But none can see UVC

[@RobertWilliams_]

That's a great video for the UVC issues coming up and a VERY CLEVER way of making a cheap UVC sensor, easily explained. Wasn't aware Glass blocked UVC so thanks for that.

[@__WJK__]

Great video... would be egually interestng to see a similar test done on "blue-blocking" glasses sold to consumers that "allegedly' filters blue-light from one's cell phone screen or computer monitor(!)

[@millomweb]

WHAT ??? Are you saying you can't see blue light ?

[@millomweb]

WJK replied: "pmailkeey - Which part of "Blue (Light) blocking" / "Filtering" has confused you(?)" It's not me that's confused.

[@__WJK__]

@pmailkeey - I mentioned blue light "blocking/filtering" ... which part of my comment has anything to do with "me being unable to see blue light"(?) www.google.com/search?q=glasses+that+block+blue+light&rlz=1C1TSNF_enUS828US828&oq=glasses+that+blockblue&aqs=chrome.1.69i57j0l7.9748j0j7&sourceid=chrome&ie=UTF-8

[@__WJK__]

@@millomweb - By all means then, please explain your "non-confused" position...

[@millomweb]

@@__WJK__ Something that blocks light is not transparent.

[@nickindevon]

As usual Clive, a great, informative and interesting video; thanks. A few things: UV doesn't sterilise, it is referred to as disinfection. The difference being that sterilisation is the complete erradication of potential pathogens whilst sterilisation is the reduction of pathogens to a theoretically safe level. The other is that UVA & UVB will have a disinfection effect but much more weakly (especially UVA). Some skin types don't react to UVA as the DNA damage is so low but UVB (high in the sunlight in South West England) can cause deep radiation burns and a longer lasting, and darker suntan as a response The same DNA damage will occur in microbes. But UVB will have a stronger disinfection effect, especially bright sunlight in the summer months on any surface than UVA. UVC is used as a sterilisation process in areas such as water and wastewater treatment because of its shorter, more ionising effect meaning that exposure times can be greatly reduced and the size of treatment plant correspondingly smaller and more effective.

[@rpavlik1]

"they're all disco lights! Very pretty disco lights, but they DON'T KILL BUGS." 🤣

[@scottmarshall6766]

Years back, a lab I worked in had a pack of "credit cards" each of which was coated with a phosphor which would fluoresce visible light when exposed to a specific range of UV. I think there were 6 or 8 cards on a ball chain kit. Each of the cards had a fairly generous range, so it wasn't a very precise test, they were used mostly to confirm the operation of UV transducers. For a while Radio Shack and Poly-Paks sold a similar single card for testing optical remote controls (IR those were), and they would glow the same way to confirm the pulsing of the diode. I'm not sure if anybody is still making that sort of thing, but there might be something available to suit our needs here. If we could find one that only glows in the UVC range, it would be a cheap, effective test you could perform with relative safety. I had a few of the Radio Shack style kicking about, but that was an awful long time ago. If I find any or find a source, I'll send one your way or let you know who has them. Maybe someone in the "BigClive" universe knows of a source? Edit - A quick search shows quite a few cards similar to the ones I remember, So many, it would take some digging to sort them all. They even have them on Amazon. This one is similar in appearance, and is made by Newport, not sure if it's the same Newport as the controller manufacturer, if so, these may be the descendants of the old ones, we used to use a lot of Newport instruments back in those days. Hope it helps. www.newport.com/f/ultraviolet-uv-sensor-cards

[@DennisGentry]

6:05 “It’s perfectly safe. . . ish.”

[@bardenegri21]

You can buy the UVC version of the chip from digi key or similar and replace it on the Adafruit module. It's like 5$ or something like that.

[@saurabhkulkarni2971]

Test was awesome, can we have the same effect created from led ones, if we can get UV LED. powerful ones

[@billrich9129]

I found that if you collect the white phosphorus powder coating inside a florescent lamp, "be careful" it will glow sorta bright orange when under UVC, no other light source will make it glow, not even a black light. You can use it to judge the UVC output of your lamp as the output does diminish over time, but the lamp visually looks the same. Been using this method for years, and only do this with UV eye protection and covered skin. Not a way to measure the output level, but you can "see" if UV is there. You have to expose the powder directly to the lamp, will not work through glass, or any container. "Might work with quartz glass" A bit dodgy, but works good. Be safe!

[@ConnorEhrgood]

1st time: Clive: "Put the glass in, and... Boom" Me: *slight chuckle* 2nd time: Clive: "and we'll put the glass in, and... " Me: "Is he going to say it?" Clive: "Boom." Me: "Nice." 3rd time: Clive: "And we'll bring the glass in, and..." Me: "SAY IT!!!!!" Clive: "Boom." Me: "HELL YEAH!"

[@alanmumford8806]

I was half expecting him to say 'safety is number one priority'!

[@haroldsmith45302]

Good test, thank you, Clive, but please implement measures to protect your eyes when handling the UVC death ray devices. Replacements are in short supply.

[@smartroadbiker]

Tape the glass to your face then you can test your glasses! Lol

[@zebo-the-fat]

but then he couldn't see the meter - no glasses!

[@jamesgrimwood1285]

@@zebo-the-fat Put the meter behind his glasses, on his face, and shine the UV bulb at his face. That'd work.

[@terawattyear]

Excellent testing and very useful for us to see. I really want a UV-C lamp but thanks to you I understand now how so many are just scams.

[@drteeth7054]

BC, brilliant video. It is amazing how you got to a measuring solution for a few £s. How about sending a link to 'Mary'?

[@Pixelwaster]

You can make a "cheap" UV-C detector using an UV-C LED. You can use LEDs as simplex bi-directional optocouplers. Just take two clear green (or red, blue, yellow, no phosphor ones) ans aim a lite one into one connected to a voltmeter. If you use really high efficiency LEDs, you can light one LED connected to another LED by shinning a lit LED close up. Hope this gets seen by Clive.

[@bigclivedotcom]

I showed that in a video where I shot an LED lamp with a violet laser and the parallel LEDs glowed.

[@Pixelwaster]

@@bigclivedotcom I missed a video? Good news - Bad news. Missed it but A NEW CLIVE VIDEO!

[@DavidSpiers]

big clive, killing his eyes and skin for all our sakes .....

[@Ch0rr1s]

Just skin. He wears glass glasses. They 'should' filter out the UVC just like the glass piece he used as a demonstration. That's at least what he said in the video where he introduced that big UVC lamp. But yeah, can't be too healthy. He's a hero :)

[@pear7777]

Well, with the shyte China is sending him, we got no worries.

[@RobertWardJones]

This is nothing compaired to when he held two eletrods connected to mains power to see how much ac voltage to take before not being able to let go of the conductors.

[@DavidSpiers]

@@RobertWardJones aye, he does like to scare us

[@johnpossum556]

Best science since your series on home wiring, Clive.

[@olipito]

Could you please give us a reading from direct sun, just to have a reference?

[@Distinctly.Average]

It is the Isle of Man, they don’t get direct sunlight through the rain clouds.

[@millomweb]

What an excellent suggestion. At this time of day, Clive, a quick trip to Oz !

[@Oheng75]

Yes.

[@chuckboyle8456]

Outstanding science demonstration of the characteristics associated with genuine UVC sources...thanks! This certainly reinforces the genuine skepticism that informed buyers maintain of many eBay products sourced from China.

[@dgriff-can]

Scammers hate him. Watch what he does next!

[@Ch0rr1s]

*clicks link* *Please buy this subscription for just 9.99€ a WEEK! you'll also get pills that add 15cm in 3 hours to 'that' place*

[@ianleitch9960]

@@Ch0rr1s 3 hours? I wuz robbed ;-)

[@61jason61]

I'm not reducing mine to 15cm 😂😂

[@Window_Hero]

Since you seem to be really getting into this, you could try making a makeshift monochromator. That's a thing that separates out light by its wavelength. Most people are fairly familiar with prisms doing this, but as you are aware, glass is fairly absorbent of the higher frequencies. Instead you could use a diffraction grating. You could have a focusing lens, and put the sensor behind a slit at just the right distance so that it's only exposed to any UVC that might be coming from the source. It would be cool.

[@Jabberwoky]

Damn, I’ve got arc eye from watching this to closely.😉

[@riotdiscoman]

Nice test. I absolutely love that you help us by showing examples. I appreciate the content.

[@crimsonhalo13]

> "USB power supply..." > has veins > long and cylindrical Yeah, nothing suspicious here.

[@ColinTimmins]

I kept glancing at it and was like... hmm... I recognize it...

[@classicshit2]

Was thinking glad it's not brown.....

[@RealNovgorod]

A bit small for a proper Scotsman though.

[@troygrant5418]

Huh......🤔....

[@hellishinc]

@@RealNovgorod Not all scotsmen are size queens.

[@Zanthum]

Another way to detect the UVc might be to detect the ozone given off by the lamp. That assumes that the lamp should be producing ozone but it's a different method. I just found this a few weeks ago. You can make test strips by soaking paper in a solution of potassium iodide and starch (pick your favorite but corn is probably easiest to get ahold of). Let the paper dry or use immediately, it needs to be wet to work so if you dry the paper it will need to be dampened when used. The test also works to detect chlorine and bromine. As I understand it the oxidizer (ozone, chlorine, or bromine) breaks apart the potassium and iodine allowing the iodine to darken in the presence of starch. Not quite what you were looking for but tangentially relevant.

[@Zanthum]

@@johncoops6897 I agree that ozone doesn't have to be present for disinfectant. I don't know if the light would also be enough to break the potassium iodide. But I more posted it as something someone else might build on for a cheaper UVC test. Which is why I said that it wasn't quite what was requested but might be something to build on.

[@Zanthum]

@@johncoops6897 I understand that. Again I was proposing the test strips method as a think piece, a jumping off point, something to spitball with/against. Instead of trying to detect the UVC directly it may be easier to find something that it reacts with, causes to fluoress, causes chemical breakdown (hydrogen peroxide maybe?) (maybe the light itself is enough to break the potassium iodide Bond as it does similar-ish things inside tissue), generates a voltage, or how about exposing yeast to the light and see how well it grows afterwards. Tech ingredients did that with ozone in a video to demonstrate ozone's sterilizing power but I see no reason that the same couldn't be done using only UVC light NO OZONE. The thought was also that Clive might choose to test to see how much relative ozone the mercury discharge lamps produce in relation to some of his other ozone generators or see how much (if any) ozone his ion generators produce in relation to mercury UVC bulbs. This test would also allow comparing relatave ozone levels in air to chlorine levels in water which are much easier and cheaper to get a test for. I was trying to share the test that I had come across recently in hopes that it might spark some creative uses for the test or spark an idea on using an unconventional/indirect methodology in testing for UVC in lamps that do not produce ozone.

[@staggerwings]

Great job! Sadly, the adafruit sensors are all sold out now. :(

[@ztynzo0]

Adafruit isn't shipping due to pandemic, but Digi-Key has most of their catalog: www.digikey.com/products/en?mpart=1918&v=1528

[@wwsxa39]

@@ztynzo0 The sensor is on back order. However the Genicom UVC sensor is in stock and only $8.78. www.digikey.com/product-detail/en/genicom-co-ltd/GUVC-S10GD/2096-GUVC-S10GDCT-ND/10475469

[@ztynzo0]

I love Digi-Key, but the mobile version of their site didn't indicate they were out... :(

[@staggerwings]

@@wwsxa39 Thanks! I just ordered 2 (in case I mess one up)

[@GRBtutorials]

It’s on AliExpress and Banggood too.

[@MikeGrayM70]

Thanks for this! I bought a UVC tube light for a sterilization box, and got one of these boards to verify that it's actually working. Passed the glass test too. :)

[@lyfandeth]

Congrats, Clive, you've totally SOLD OUT THE WORLD SUPPLY OF ADA1918. Any alternatives to suggest? Or will you sell or rent me yours? Please?

[@kwinzman]

chriswesley.org/spectrometer.htm

[@james0x2a]

kwinzman "The i-Phos can see wavelengths from approximately 420 - 980nm". This doesn't cover the UVC spectrum.

[@GigotDagnot]

there are a lot of this component in France. (gotronic for example). You could try. maybe they deliver to your country.

[@kwinzman]

​@@james0x2a Thanks that's a good point! However I know mine works down to approx 300nm, it's just less sensitive. Also if it has a peak at 390nm you know it's just a disco light ;-) On the other end of the spectrum I have successfully used this tool to detect a fake IR940nm flashlight off ebay that was actually a 850nm one. So I can definitely recommend it for the price.

[@ninjageezer6802]

www.okdo.com/p/adafruit-analog-uv-light-sensor-breakout-guva-s12sd/

[@alancordwell9759]

Very well presented Clive, what a learning experience this channel is! Stay safe :)

[@20thcenturyboy85]

AWESOME Content Clive!!!

[@kuhrd]

Great test Clive, it is annoying that it is not cheaper and easier to get ahold of a spectrometer in that range you are looking for since that would definitively prove that there are no useful peaks in the UV-C spectrum but the use of glass as a filter proves that fairly well. It would be interesting to see what you get off of fluorescent tubes especially when they get old and the phosphors begin to flake off inside. The glass of the tubes should shield fairly well though compared to the quartz in the UV-C lamps.

[@tomservo5007]

is that power bank from Amazon's questionable 'essentials' category ?

[@kwakamonkey]

Asda used to sell them , Made by ONN (Asda is Walmart for the non Uk people )

[@bigclivedotcom]

It did indeed come from ASDA.

[@JMDSupra]

Thank you so much for this video,,, I needed to understand UVC so I could get a real one to help sterilize a room for my father. He is about to get treatment for cancer and his immune system will be weak, While he is not in the room I wanted to be able to get a UVC kit to help kill germs in the room he is staying in. I was worried about getting a lamp that was fake, Now you have educated me so I know what to look for. I Also Found UVC test cards I can buy that will test the lamp. thank you !

[@urugulu1656]

ultimately someone who deals with it like an engineer.

[@TheSergeiFranco]

I have convoy S2+ with 365nm LED. It looks pale blue (not violet) and it does burn skin when placed point blank (it starts to smell after about 10seconds). It also lights up phosphor in other (normal) LEDs, as well as produces voltage on said LEDs.

[@Nono-hk3is]

Hell yeah, shout out to Lady Ada.

[@daleridpath]

Love you clive, with a passion that will never die!!

[@adcuz]

LOL @ supposed germicidal light having DMX

[@rexsceleratorum1632]

To be used with "killing me softly (with his song)"

[@ratanats]

Great test and is sufficient to prove whether a lamp is emitting UVC, or not. I bought a 2020 Newest 60W UV Germicidal Lamp Led UVC Light though eBay US from a seller named "etrade520". Seeing that the LEDs look ordinary with plastic coating, I did a similar test and concluded that they have nothing to do with UVC, but are emitting plain blue "disco light". Returned it and asked the seller to pull down his add, but he has not, yet. Unfortunately, I see that he has sold 100+ so there are a lot of people who think they are protected. Very sad...

[@bigclivedotcom]

Be careful with the lamp. I got one too and the exposed solder joints are live at mains voltage.

[@someguy2741]

Seems like a reasonable ghetto science test to me. Incorporating the glass gives a good control to make it valid. Are there other filter medias that would block only UVA or UVA/UVB?

[@Muonium1]

Polycarbonate blocks everything

[@someguy2741]

@@Muonium1 Perfect. So... if the sensor reads something... the polycarbonate would block UVA/UVB/UVC so it would show background "zero" of the sensor. The glass blocks UVC. So any difference would be the UVA/UVB.

[@Muonium1]

@@someguy2741 more or less. float glass blocks around half UVB, averaged over the full width of the band.

[@someguy2741]

@@Muonium1 I think it should be good enough for "detection". And it should also allow for relative strength comparisons. I doubt if this level of gear would be able to be calibrated but for home gamer level "safety" checks it should be plenty good.

I have learnt a lot from you and UV lamps and can see how people get conned and how theuy can damaged themselves. The fake ones give people a false sense of security thinking that UVC is only killing bugs and not destroying them. If you buy a fake one and then get a real one you could reaally do yourself some harm. Thank you

[@HowToGuys]

You're best👍, exactly what I want to see!

[@HowToGuys]

I'm wondering if you can test this 280 nm UVC led,is it good replacement in water purifier systems? www.ebay.com/itm/UV-LED-Diode-280nm-Seoul-UVC-LED-SMD-3535-315nm-400nm-Chip-Ultra-Violet-light-/333579820525?_trksid=p2349624.m46890.l49292

[@jimknock]

Thank you very much. You have clearly revealed a lot of things. I have been searching for answers for a long time.

[@chriss8825]

I have been in a similar predicament. I purchased a 25w ozone free UVC light from amazon a while back and wasn't sure if it was actually effective. I tried some test with yeast, but the experiment failed. One 'neat' trick I found by accident recently: Place the UVC light by a new bright yellow banana for ~30 minutes. Then compare that banana to a control banana 24 hours later. The UVC banana skin gets very 'dark' even tho the banana inside is still fresh. Note: To avoid melanoma cancer the UVC light is in a sealed container and I always activate and deactivate the light remotely.

[@GeorgeWMays]

Fun. Interesting. A perfect Sunday passtime; a fresh ice tea, my dog at my feet, my cat asleep on the desk, and a Big Clive video to watch. Thanks. It is appreciated.

[@robinvince616]

Very informative test, Clive - well done! It was interesting how glass failed to block UVA to the same extent. As you know, all LEDs act as sensors to a degree. Perhaps a tester for UVC could be made by employing two UVA LEDs as sensors working in opposition (to the two inputs of an op-amp maybe). If one had glass over it and the other not, with suitable relative sensitivities set, maybe a meter could be persuaded to move one way for UV A and B (and visible light) and move the other way for UVC. Then you'd have a UVC detector without needing a true UVC sensor.

[@robinvince616]

Actually, a quick test here shows the UV LEDs are probably sensitive enough to simply put two in series opposition connected straight to a voltmeter. Connect a 1M ohm or so pot across the meter with the wiper to the junction of the two LEDs. With some glass across one LED only, adjust the pot for best reversing voltage difference between UVA and UVC. I have no UVC source here to prove it works, but a UVA torch shows encouraging results, while a very bright white torch is not detected at all. LEDs are only sensitive to their own wavelength or those shorter it seems, so hopefully UVA ones will detect UVC.

[@antonsund7170]

I don´t know if anyone else commented that, but I remember back from school when we "measured" the wavelength of a specific LED with a double-slit thingy and some lenses. There were only some measurements to be taken with a ruler and put some numbers in a formula and get the wavelength of the light source. Of course, these results were quite sketchy, however, if You measured it carefully and got the dots clear and not blurry through lense movement, the results were ok. This could be another cheap test to see, which wavelength you get mostly.

[@bigclivedotcom]

The problem is that UV is invisible.

[@antonsund7170]

@@bigclivedotcom Most of it is, yes. However, as You figured most lamps do have a visible part which might be enough to do the lense movement and so on. However, if not it might be possible to use a photodiode (just like you already did) to find out, where the maximum aka dot is brightest and then measure from there. I remember myself doing it with an IR LED which was completely invisible. It was a bit of a pain to set up but did work in the end.

[@martinwinfield2935]

I was extremely interested in this test. Very good comparison, it would be interesting for you to test the UV tubes used in water sterilisation. Thanks for making the video.

[@thedevilinthecircuit1414]

What a great way to prove the scam--with penny parts! Big Clive, you sir are a genius.

[@Captain_Char]

Hey clive, I have a air sanitizer as they're called here, but the UVC light inside the machine is causing the plastic to break down at an alarming rate, so much you can take a finger and rub the layers off with a finger

[@erickcampos50]

Thank you for this excellent service, sir!

[@RelakS__]

Hey, Clive, buy some Hungarian Forint banknotes. One of their safety feature that a picture on them gloves in different colour in UVC light than in UVA. For this reason, there are banknote checkers with UVA (365nm) and UVC (245nm) light sources. e.g.: In the front of the 500HUF (right now it worth about one and a quarter pounds) you can see a yellow "500" and a green horse with a soldier in UVA, while they are brown and orange in UVC respectively.

[@233kosta]

I have a 360nm led torch and the visible colour is a fairly dim warm/yellowy white

[@gnarflord4547]

Thanks for the insights, clive! That's quite interesting stuff. I share my household with someone who definitely belongs into the risk group of our current situation. Thats why I've recently converted my old EPROM eraser into a virus-eraser and try to sterilize anything with high contact potential like keys and doorknobs. I'll definitely order one of those sensors, just to expand my platoon of random test equipment :)

[@gyka3188]

Hi, BigClive, I'm a SmallSwiss guy ;-) Looking for info about UVC lamps I found your site. Very interesting and not only for UVC lamps: congratulations for your work. UVC so: the video "Testing UVC lamps with a cheap UVA/UVB sensor" is exactly what I was looking for. But I suck at electronics, a bit better at electricity. I bought the Adafruit module and I'll need an explanation on how to connect the usb battery to it and the connection for the tester. (Maybe a diagrammatic explanation of how to connect the usb battery and the connection for the tester.) Thanks In advance

[@mosfet500]

Clive, thanks for this. I just bought a couple of those boards, I think I'll write an algorithm to linearize the UV curve for better UVC output. Rob

[@clee1023]

Like the test. What is the make of all the VU lights used in this review?

[@3amali1]

Clive, to be fair to those LED lamps are most likely 395 nm so still can be called UV, but to claim they can sterilise is maybe a bit too much! I saw some cheap optical spectrometers on ebay which could measure 350 nm all the way to 800 nm so those could be handy and make up a nice video to identify the fake claims though they won't be useful for the UVC band but at least show the true wavelengths. Nice work, and if I get hold of a UVC meter (which am trying) I will let you know.

[@mangethegamer]

Please test grow lights and how they perform. It's of importance for us who grow basil in our attics

[@herseem]

Basil.... yes.......

[@chualc]

The specifications for the LED 'disco' UVC states wavelength produced is 200 nm to 360 nm. If that is true, then quite a lot of UVA and UVB might have passed through the glass as well... which might explain why the voltage change with glass is minimal.

[@mikm.6375]

Very thorough as always Clive, Disco lights are not UVC & funny part is as I was after mine to sterilize my PPE I looked at those & thought 'Noooo these are toys / Gimmicks at best' 💪💪👆👆✔✔ Keep up the great work!

[@omsingharjit]

I heard by Derek Muller in his one of video that all Ccd sensor are uv sensitive but the glass lense used in it block the most of uv light but I wondering if we use parabolic lense to focus on Ccd it will also pick up light so easily .. So can you do my thought experiment in reality ?if it's possible to turn normal camera into uv sensitive .

[@SardiPax]

Good test, but have you seen there are tanning indicators that presumably monitor specific UV flux? They are made of polymers that reversibly change colour when exposed to UV. May be worth investigating their wavelength range.

[@robinsonlabs]

Brilliant test Clive! We are waiting to test a batch of gold plated saphire windowed 3535 uvc/uva combined chips however, Getting the data sheet seems to be the hardest part!

[@AM-yj5yc]

I wonder if the wand "with loads of safety interlocks" is turning off because it also has a safety interlock in the form of mercury switches or some other means of detecting gravity orientation changes, since it seems to turn off if you quickly switch it around from facing down to facing up. If so really smart idea given these things are indeed so hazardous; you'd assume with something like that that there wouldn't be too many situations where the lamp rapidly changed orientation during regular use, more likely only to occur with a drop or turning it upside down forgetting it's on. Just a blind guess though. Could just be a timer.