385-395nm UV led on ebay....

I bought 10 of these from hong kong. Nice to have a small amount to buy (10) and at 3.00 after shipping they still are only 30 cents a peice. You can get larger quanities and save even more money, but I've got enough things and projects going on, so I won't be making a 100 UV led grid anytime soon yet.
link

Why I chose this one is because it says 385-395 nm range instead of the usual 395-400nm. So hopefully these will be no greater than 395nm, and possibly lower!
2,000mcd that's about average for UV leds I see around.

Well see. I don't have any other UV leds to compare with but I might order 1 uv from lsdiodes to compare sometime. I can compare with my purple led computer case fan to see if it's any deeper... I'll report back...

I got some of the same a couple days back. I'm somewhat dissapointed, they don't cause things to flouresce nearly as well a standard bulb lamp. It could be my batteries though as I did a quick test w/ out proper current.

Hmm. have you compared them to other UV LED's?
Get back to me if you do re-test them. I'm still waiting for them to arrive.

I got a few UV LEDs from a forum member. I first tried one on 2 AA batteries (Alks, NiMHs and finally Lithiums) and was less than impressed. I rigged up something so I could use three AAA Alks and was definately impressed. I'm not 100% sure of the wavelength, but from other UV products I've owned or tried, I'd guess this particular one was no longer than 395. It puts out relatively little white light and causes items to flouresce from several feet away in complete darkness on 3 cells. On 2 cells, certain things wouldn't flouresce well even from only 6" away.

Point is, 2.4v just wasn't enough to make the LED do what it is supposed to.

The same member sent a 8mm (or maybe 10mm) UV LED and while it was radically brighter, it was obviously of longer wavelength.

Havn't tried them against other UV leds. But cratz is right for using 3 cells, 2 just are really weak for this led. I tried with 4 button cells and saw very little increase. For three cells these LED's (ebay - hktaiyuen) are definately bright. I'm a little skeptical that the wavelength is actually 385. I'd say its more toward 395-400 range. About the only thing I could get to flouesce was higlighter marker. Not great for forensic work. They get a thumbs up for brightness/ thumbs down for wavelenght from me. I got some comparison pics below.

First pic is ordinary Blacklight tube-



Second is single UV LED (3cell)
Both shots taken ~ 1.5 ft away from white paper w/ highlighter same cam settings.
Notice the lesser intensity of the yellow.

Hmm. So are these just as good as 395/400nm LED's or worse?

I was hoping theyd be no higher than 395 vs getting some that were stated: 400nm or 395+ nm.

EDIT: btw, uv leds need more than 3v to run. 3.6 average like blue/white.

The 385 nm might just be e-bay marketing. As always, caveat emptor. Most others from hong kong seem between 395 to 420 at the worst.

Disapointing, but thanks for the review.

fusionman, would I be worse off with these, than say a standard 395-400 that's sold? Or are they the same?

I think with buying most any LEDs on eBay, you just sort of get them and compare them to others you have. Most sellers lie like dogs as to candlepower, wavelength etc...

Here is a beamshot I took of the same two LEDs. The left is running on two fresh cells, the right is on two fresh N cells plus one NiMH. This shows that they really need three cells.

my 3 aa cell 7 led 385nm uv light is lower frequenecy than 400nm

it glowes purple - dimm purple not blue

it makes things fluresce brightly

The closer to 365 nm - the less visible the light is to the naked eye.

I'm fairly sure these are 395 nm now.
They don't make US currency glow, or those uv features on credit cards and licenses. As kite points out, you can't directly judge, only based on the flouroluminesce [if thats not a real word, hopefully u know what i mean /ubbthreads/images/graemlins/grin.gif ] of certain objects at certain wavelengths. This LED has a very good peak wavelength though, theres very little bleeding as far as I could tell from a simple color chart.

Anyone tried the ones from besthongkong? I'm guessing they may come from the same plant as these.

As markdi mentioned, they glow a deep purple / violet. Wheras a blacklight does not have a similar visible region.

Here are some currency pics - hopefully the purple shows better on the led as opposed to my last pics.

LED



Blacklight

so the strip doesnt glow at all with the led? What freq do they start to glow then at? 380? 375? ?

385 and under for the strip to glow I believe.

I make them glow with my Inova X5T UV and they are rated at 395nm. They shine bigtime! Many companies lie about thier wavelengths. Inova does not.

Hope my new Nightcutter 5CSI (coming in the mail soon) is a true 375nm. That would be awesome!

no one lied about the wave length of my 7 led 3aa 385nm
light I bought from ebay for a total of about 26 bucks shipped.

[ QUOTE ]
markdi said:
no one lied about the wave length of my 7 led 3aa 385nm
light I bought from ebay for a total of about 26 bucks shipped.

[/ QUOTE ]

That would be a good light to recommend then. Some do lie though. I can tell you that whoever sold the light to fusionman lied to HIM. If his light really was 395nm then the strip would glow and the images would appear on his credit cards...

...or his money and credit cards are fake. /ubbthreads/images/graemlins/yellowlaugh.gif

Anyone used Innova UV Keyring torch to make strip to glow ?

It should be more than enough to make the strip glow.