How to test if UVC LED is working?

[Nutball]

I got a cheap 60W UVC LED for hopefully killing mold under the house, but when I first saw the bulb, I noticed no glass lenses on it (I got the non ozone version). I also noticed when powered on it didn't look like the right color. I did glance at the bulb from about 40ft, and further observed it's faint reflections from another room to minimize risk. It looks quite blue instead of the purplish greenish blue I've seen from glass UVC tubes. I just now checked, and it seems to be a lighter blue, so maybe it needed to warm up.

Anyway, how can I test that it really is putting out strong UVC? What can I put near it or filter it with to observe definite results of UVC output?

 

[FireMyLaser]

60W UVC LED? That has to be fake. Are the LEDs having a yellowish coating on them when turned off?

 

[Cyparagon]

There are several at-home tests for UVC I'm aware of.

Irradiating your skin with it produces a distinct smell, a bit like musty burning hair if I had to try and describe it.
It will give green bananas a 'sunburn', discoloring some of the pigments brown within minutes.
A broken shard from a fluorescent lamp will glow under UVC, but not UVA/vis.

I can say with 99% certainty your UVC led cob is fake though. UVC LEDs are not made in those power levels, and certainly not for a mere 2-3 figures.

 

[Nutball]

They do look like normal yellow LEDs. I saw an article where someone suspected the same bulb a fake, though they never tested if it had any short wave UV output, they simply bluffed the seller into giving them a datasheet showing it emits in the 300-400nm range or something, maybe 430's. He did show genuine LEDs look like glass and are covered with glass. I was suspicious from the start because it had no glass to prevent high levels of ozone.

I'll check for a smell later tonight, they do mention it can make a room smell burnt.

 

[FireMyLaser]

These are well known to be fakes and not emit any UV whatsoever. The have blue LED chips covered with phosphors to look like UVC discharge tubes. I would demand the money back just on principle. People get these for covid to disinfect, but cause another reason for spread instead.

 

[Nutball]

Stupid me didn't read the 390nm in the description. It definitely wasn't purple, but not really a natural blue either, which made me not want to risk a closer look. They have a 254nm glass tube version, only 25W

 

[Jim H]

A true UVC would have no visible light coming from it, yet would make fluorescent materials glow. As said above, UVC's come nowhere close to 60 watts, not even 1 watt, and can cost in the thousands of dollars depending on wavelength and power, and many hundreds at the least.

 

[Jim H]

390 nm is UVA, not good at killing anything, especially being at the high end of the range. UVA is 315 nm-400 nm

 

[gazer101]

UV lamps should cause most glow-in-the-dark materials to strongly fluoresce (and you should only see the glow from the fluorescence, not the UV light coming off of it). Otherwise you probably have a near-UV violet LED which is pretty much useless for disinfecting anything

 

[Nutball]

I have a 4W glass tube UVC bulb that seemed to bleach red serratia bacteria in a highschool experiment. Obviously I can't see the UVC, but I can see a mix of blue green and purple plasma in the tube.

So, what's this 390nm 60W light good for now, any ideas? I'll keep the remote base to use on a 254nm glass tube, because the bases cost an over priced $20 alone, and that's what the whole kit cost, so no sense in returning it. I will call them out on the false advertising.

 

[gazer101]

You can use it to cure some resins, solder mask, some types of glue, etc.

 

[Jim H]

It should make a lot of things fluoresce, but you will also see the light as well. Might be less noticeable if you got a filter to block anything over the 390, as it probably produces some of that as well

 

[Nutball]

It's weird lighting up a room with it because a normal 20W "black" light would brightly light up white and fluorescent greens and oranges, but this thing is so bright you hardly notice greens and oranges over everything else being illuminated. Not very purple like 405nm, but has the same blue look on white stuff. It didn't charge glow in the dark stuff quite as well as my defocused 30-70mW 405nm laser at the same distance.

 

[Alaskan]

When searching for a solid state UVC source I found nothing suitable, and the LED's I found at that wavelength put out only a few milliwatts are not cheap. I bought this instead along with a inexpensive bedside lamp to use the socket from and mounted it in an old nail salon sterilizer box which had a bad 8 watt lamp and circuit board, ripped that out, and installed one of these which is more powerful and also produces ozone inside the box, a double whammy against virus'. I use it for masks, 10 minutes each side should be far more than enough exposure, don't leave it hours or the mask will smell burnt and degraded by the UV and ozone gas. Some elastic straps loose their elasticity in this box, some don't.

Amazon.com: UV-C Light 25W UV Lamp 110V with Ozone Ultraviolet Bulb Sterilization E26 Base.: Home Improvement

Amazon.com: UV-C Light 25W UV Lamp 110V with Ozone Ultraviolet Bulb Sterilization E26 Base.: Home Improvement

www.amazon.com

 

[Cyparagon]

Masks are incredibly porous, my dood. The light isn't going to do much. But viruses die off rather quickly outside of people anyway. so sticking them in a box helps.

So, what's this 390nm 60W light good for now, any ideas?

You said it wasn't purple, so it's not 390nm. Your camera shows it as ice blue, which is simply royal blue with a tiny bit of phosphor, as confirmed by your close up picture.

It's a bluish white light source. Light your room with it. It's not really good for anything.

 

[Alaskan]

Masks are porous to capture the virus to stop you from breathing it, at least to reduce it due to being structured in a kind of labyrinth, that is why what I am using producing UV light for the outside and the ozone for inside and out it is very effective. I research this from medical PPE resources, not an unfounded wild stab.