22 Feb
2010
22 Feb
'10
11:57 p.m.
On Mon, Feb 22, 2010 at 02:10:43PM -0800, Chuck Guzis wrote:
On 22 Feb 2010 at 22:35, Alexander Schreiber wrote:
The local trains also have some locomotives with LED clusters for tail
and front lights (but they also have incandescent front lights as well).
Although by now the LED light output in general
is high enough that
they are used in traffic lights (a lot of the traffic lights around
here (Zurich) use LEDs).
I see them in tailights for buses and trucks also. They have a
somewhat different color (narrower spectral distribution) than
filtered incandescent lamps.
Initially, I mystified my wife by being able to pick out LED
stoplights from several blocks distance. I'm very sensitive (for
some unknown reason) to flicker and those line-powered traffic lights
evidently were pretty high on ripple. More recent ones don't display
that effect, so the power supplies must have improved.
However, to my eye, the biggest abomination are cheap Christmas tree
LED lights with very pronouced flicker. I haven't researched it, but
I suspect that the LEDs in such strings are hooked in series and used
to self-rectify the line current.
Those have been popping up around here with a vengeance. You can usually
pick them out by color alone: really _white_ instead of the yellow to
yellowish white you tend to get with incandescents.
I've also seen decorative light lines on at least one of the Zuerisee
passenger ships here: It's got to be LED since it
a) changes color
b) has very "clean" colors, the typical narrow spectrum of LEDs
Regards,
Alex.
--
"Opportunity is missed by most people because it is dressed in overalls and
looks like work." -- Thomas A. Edison