I see that Home Depot in Canada is now handling some LED bulbs with a title
of nightlights or something similar. They appear in the shape of the usual
medium base incandescent shape and have a white translucent dome over the
top if them. The ratings are so poor they could only be used a nightlights.

$30 ea.
7 Watts
155 lumens.

While there may be useful places for these nightlights, they don't look that
useful for me. Their efficiencies are barely as good as many incandescent
technologies at 155/7 = 22.14 lumens/Watt.

I am still looking for a decent PAR30LN LED bulb that can be used over my
sink with an X-10 switch module (yeah ..it dims) 1000-1500 lumens would be a
good brightness.


"Josepi" wrote in message
...
Things are definitely improving with this technology!

I still suspect, as the article in the link I pointed out (another post)
the LED manufacturers are cheating the measurments a bit as they don't
include ballast energy (they can't as they don't know the circuit) and
they don't include the losses of the lens and/or filter and as you article
describes, the input power vs output power.

Thanx!


"Don Klipstein" wrote in message
...
Yes. The usual white LEDs have blue-emitting chips coated by a phosphor
that absorbs some-most of the blue light and converts it to a
yellow/yellowish broad band whose spectral content typically covers
mid-green to mid-red. Some of the blue light is not absorbed but passes
through the phosphor, to mix with the yellow/yellowish light so that you
get white light.

Nowadays, some of these blue chips used for white LEDs are achieving
around 40-50% efficiency. The most efficient white LED on the market
that
I am aware of, Nichia NSPWR70CSS-K1 at 20 mA, is a goodly 40% efficient
even after losses of the phosphor. At 20 mA, it is supposed to typically
achieve 150 lumens/watt.

- Don Klipstein )




In article , Josepi wrote:
How can the efficiency of a white LED be higher than it's constituent
LEDs?
Is this due to phosphour screens used?