On Sat, 20 Feb 2010 19:28:08 +0000 (GMT)
ard at p850ug1.demon.co.uk (Tony Duell) wrote:
Incidentally, I was amazed how little current a white
LED needs to give
some glow.
The Cree XP-G gets up to 140 Lumen at 1 Watt. It can be driven with
3 Watts i.e. 1 A current but efficiency will drop. So it gets "only"
around 350 Lumen at 3 Watt. I have some of those LEDs. They emit so
much light that it will burn your finger when you touch the top of the
LED. This is only caused by the energy of the light that gets absorbed
by the skin. The LEDs stays cool. (OK. They are mounted on a big heat
sink.)
Nichia has low power LEDs that achieve up to 150 Lumen per Watt.
White LEDs have become one of the most efficient light sources.
--
tsch??,
Jochen
Homepage:
http://www.unixag-kl.fh-kl.de/~jkunz/