I've had very good luck purchasing blue and white LEDs from an ebay
seller in Hong Kong. He ships everywhere for a fixed price. Very
reasonable. There's an electronics/parts/LEDs category on ebay, so it
should be easy to find the source.

Paul Mathews

Old Nick wrote in message . ..
On 30 Jan 2004 11:05:59 -0800, (Paul Mathews)
vaguely proposed a theory
......and in reply I say!:

Hi, Nick. You have the right general ideas about lux, candela,
lumens. You can find more at my LED FAQ page:

http://www.pioneernet.net/optoeng/LED_FAQ.html

OK. I will check that out for sure.


The latest LED technologies put out as much as a few 10s of lumens per
watt, but input power is usually limited to about 1/3 Watt or so per
LED. Compare that to a 50W halogen bulb (with its ~10 Lumens/Watt)
and you can begin to see why incandescents still have an advantage,
especially for spot lights.

LEDs are really at their best when you need colored light, since the
filter required to achieve colors with incandescents absorbs much of
their output.


I could see the difference. It was just that with the way LEDs were
being written up, I was wondering if I was actually comparing apples
with apples at all.

If you need lots of lumens, it takes lots of LEDs. Those that have
the chip up close to the 'dome' spread their output over a broad angle
and vice versa. Broad angular coverage means less intensity and vice
versa.

However, specs remain confused and confusing.

Ah! Good! At least it's not just being dumb again. :-

The advice I
continue to give after some years at this is this: obtain some samples
and use your eyeballs to decide what works best.

Hah! Trouble is some of these places want to sell you 20 at a time. IN
Oz, at $4 each, an experiment can get pretty expensive.


Another excellent source of visible LED info:

http://members.misty.com/don/ledx.html

See my later post on this thread. Thanks

************************************************** ** sorry
remove ns from my header address to reply via email

Spike....Spike? Hello?