10 Nov
2011
10 Nov
'11
1:41 p.m.
On 10 Nov 2011 at 20:00, Tony Duell wrote:
I see, so the claim that I've seen made several
times that 'LEDs don't
burn out' is downright false (not that I ever thought it was true,
after all, I've replaced plenty of dead LEDs over the years...)
I'm sure that after hundreds of thousands of hours, a white LED will
still have a visible glow, even though visible light output will have
dimmed and color-shifted away from what it used to be.
Re: spectrum--I seem to recall reading a couple of months ago in one
of the trade rags that someone (Cree?) is putting red LEDs together
on the same fixture as their high-power white ones.
I haev used LEDs in Newtonsday decorations, but
running them off a DC
supply (so they don;'t flicker). The reson was that LEDs are easy to
drive from logic circuitry, so I'v ehad Newtonsday decorations
controller by a PDP11, PERQ, HP41, HP71 and HP48 over the years.
I've run mine off a full-wave bridge and that seems to handle the
flickering, but the light quality is still very harsh. I'm used to
the warm glow of incandescents, not the ultra-pure point-source
colors of LEDs. They're supposed to remind you of candles, after
all, not someone doing TIG welding.
--Chuck