some observations on those 360nm UV leds

I just received the leds from the GB. Immediately, I powered one up with 2 x 2016, the same cells used in those keychain led lights. Few observations...
1) There's not much to see; the light is weak; it doesn't fluoresce things much at all.
2) I've been told that 360nm should fluoresce the US $100 bill well. Uh uh. Can't see Jack sh*t. For a moment, I thought I got a phony bill. Fortunately, I have a small UV fluorescent lamp. Using that I can see the red stripe. Pheww...
3) A donut hole in the beam? I've never seen a 5mm led with a donut hole until I got these.
4) Compared to other UV lights I have, the 360nm led does not fluoresce things nearly as good. In fact, most things that lit up like a Christmas tree using my other UV lights, would not react to this 360nm led at all.

Obviously, these are only my observations. I'm in no way trying say anything negative about GB. chimo did us all a favor, and I'm thankful for that. Now, about these leds, I'm not sure if I want to waste a good X5 and put these leds in it?

If anyone has seen positive results from using these leds, please let me know how.


Thx,
ernest

I'm interested to hear any info on these, mine haven't yet arrived and I'd like to know how to use them properly.

Try them on the front of your Amex or Visa cards.

I have. It's too weak to show the dove. Even my eBay 8-led UV can show the dove. It really makes me appreciate the Cree 7090 UV a lot.

I replaced a turquoise LED with one of these UV LEDS into a Photon III. If you are in the dark, you can see the strip of a $100 flouresce from the front of the bill.

Jeff

vacuum3d said:

I just realized that I posted this in the wrong forum. Admin, please move this to the LED forum. Sorry.


I just received the leds from the GB. Immediately, I powered one up with 2 x 2016, the same cells used in those keychain led lights. Few observations...
1) There's not much to see; the light is weak; it doesn't fluoresce things much at all.

Click to expand...

Did you check to see how much voltage/current was being supplied? The power requirements of the 360 may be a bit higher than others (due to a physics principle) and 2 x 2016 may not be supplying a high enough voltage under load.

I'll let you know when mine arrive.

Daniel

pitbull, if you didn't have the turquoise led, do you think the stripe would have shown up?


gadget_lover, thanks. I guess I could try it with a Li-Ion as well.

If you are just hooking the LED up to the cell (direct drive), the coin cells probably didn't have the oomph to light up the 360nm LED. The Vf is 3.6V min to 4.5V max with typical Vf listed as 3.8 V for If of 20ma. Try 3xAA (could be any size cell actually, but everybody has some AA cells, right?) Ni-MH cells in series, just not hot-off-the-charger ones.

Someone else recently posted about replacing the white LEDs in a multi-5mm LED light with the 360nm units and got GREAT results. He indicated that the 360nm units caused really-really good glows from objects with no visible light purple from the LEDs to wash over the object.

Yes there is a donut hole. I just tested one though that I have laying around that didn't have one. These LEDs have a very Narrow Bandwidth. That means they emit 360nm and nothing else. A florecent UV bulb will peak at 360nm, but also emit other wavelengths. Some items may need a higher wavelength to glow, and the bulb emits that so it glows, and the 360nm LED, is only 360nm. The microwatt they emit is very low compared to 395nm leds (miliwatt) so you need several for better results. I have good results with these in a Dorcy1AAA though, and can see the logos on my CCard.

These have higher VF and the coincells may be sagging to below the Vf. If one were to put these on a Constant Current regulator, I think we'd get the best results. Perhaps 20 of these on a BB400 would be interesting. We'd know they were all getting close to 20ma each then, regardless of the higher VF. If I had a host/money for all the stuff that is the route I would go. I think it would perform the best that way.

Powering a single 360nm UV led from Chimo's recent group buy with a pair of fresh 2016 coin cells will, I repeat, will overdrive these leds. Fresh 2016's will cause about 85 milliamps to flow through these UV leds during the first few seconds with a very slow current decline after that. They will become hot in about ten seconds.
It's best to keep the drive current to these leds below 25 milliamps in order to prolong their life. There is very little UV output increase when going from 20 milliamps up to a steady 25 milliamps.