Comments on: Merry Christmas to Me!

By: Ben

Ben — Wed, 04 Jun 2008 04:55:28 +0000

@Jkx, I was going to suggest SureElectronics to the people here wanting to know about LEDs, too. In fact I just bought nearly $50 worth of components from them today. Two things:

Email asking for extra shipping discounts, they aren’t much, but they help. Tell them exactly what you want, and ask for a total price, saying that the combined shipping they offer is not reasonable.

They are three users, look under: SureElectronics, SureElectronics2, and SureElectronics3

By: Dave

Dave — Mon, 07 Jan 2008 16:03:16 +0000

Good luck with the white LEDs. Use a bit of caution, though. Some of the (early?) white LEDs suffer from phosphor degradation at an astonishing rate. Some of these things go dim after only a few dozen hours of operation. I haven’t yet figured out how to tell the bad ones from the good ones, other than by running one for a week or two and observing the brightness.

As for the UV output, while I no longer have access to a spectrophotometer, I don’t believe that they put out too much short wavelength UV. Most of the UV LEDs (which I do have a few of) seem to put out somewhere in the 3900 Angstrom range, which is near UV. Anyway, it would be interesting if someone with access to a spectrophotometer could run some plots of the output. I’m kind of curious as to whether the phosphor being used in some of the white LEDs is a broad band phosphor mix, or whether it’s composed of a couple of bands (Yes, I know I could build my own spectrometer, but it’s a matter of time.).

Yeah, LEDs are cool. But, they sure have improved since the effect was first discovered in 1906 (by Round?). That’s one of the reasons I’ve enjoyed playing with them over the past 30+ years.

Dave

By: Jean

Jean — Sat, 05 Jan 2008 12:17:07 +0000

I got 4-legged white LED’s identical to yours from a big, reputable French retailer (I’m French BTW). Yeah those babies rock. I’ve compared them to regular 2-legged 50 candella LED’s and find the 4-legged ones are a lot easier on the retinas.

My theory is that blueish white LED’s (and blue LED’s too) must emit some UV. I don’t have a spectrometer to test that theory though.

I’m getting fed-up with replacing my “energy saving” bulbs twice a year so I’m looking for a nice cheap white LED to make my own bulbs.

I couldn’t get the manufacturer and datasheet for the 4-legged LED’s, only the direct voltage and current (even had to deduce the pinout) : if you have them, could you post them ?

And to make you feel better about overseas shipping… when I order from Parallax in the US, shipping for a pound of integrated circuits costs me 85 dollars, and it doesn’t get to me any faster than your LED’s got to you.

Jean

By: Richard

Richard — Sat, 05 Jan 2008 10:32:14 +0000

Thats the norm for asian sellers on ebay, they are charged on the sell price not the total so they jack up the delivery to get their profit. You just have to accept that they are gouging you on the delivery.

By: Matt

Matt — Sat, 05 Jan 2008 06:26:42 +0000

Would you link to that driver you picked up? Looks like a decent little item I need to add to my inventory.

By: Jkx

Jkx — Sat, 05 Jan 2008 04:20:40 +0000

2 things, HongKong sellers usually make money on the shipping, so not really strange they don’t want to drop this price. I ever bought some stuff on ebay from this country, and the final ebay price was: 1$ item + 99$ for shipping.

I usually buy this kind of stuff from SureElectronics (ebay). They are serious (hum, one time they forget a pack, but send it for free), offer some good prices, and accept combined shipping without issues.

Bye bye from France