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Re: [APD] LED Lighting
Date: Mon, 29 Dec 2003 16:17:48 -0800 (PST)
From: "S. Hieber" <shieber at yahoo_com>
Subject: Re: [APD] LED Lighting
To: aquatic plants digest <aquatic-plants at actwin_com>
--- Wright Huntley <whuntley at verizon_net> wrote:
> Message: 6
> Date: Mon, 29 Dec 2003 13:14:57 -0800 (PST)
> From: "S. Hieber" <shieber at yahoo_com>
> Subject: Re: [APD] LED Lighting
> To: aquatic plants digest <aquatic-plants at actwin_com>
. . .It
certainly isn't up with the CF lamps I was immersing a
couple of years
ago. Those carried some truly lethal Voltages/currents
and the current
in water would have been more than non-trivial!
You were putting your bulbs in the water on purpose? I know
this is done with sleeveless UV lamps but don't recall any
other examples. If intentional, what were you up to?
No. Not in water. I had them in a plastic tube, but sweated a lot about
the hazard if one leaked or cracked open.
Illumination from below the water line is very unrestricted by such
nasty optical effects as light-piping. You have never really seen them
until you see a herd of Rasboras (I like the *espeis* that Amanosan
prefers), illuminated from inside the tank. I love Lampeye killifish and
most of them become spectacular when the light is no-longer propagating
straight downward. Like windowlight, but way better.
> Wright do you really think transistors are needed in a
> power supply? Low voltage DC, a rectifier and some
> resistors ought to do the job. But with enough to light
> tank, even the resistors would be redundant, no?
The high impedance of a transistor collector is probably
all the stuff you have suggested. Don't forget that
often way cheaper than resistors, these days, unless you
individually packaged ones. Resistors can act as
but must waste a lot of power to do so, and I find extra
heat a problem
with most lamps. A 5V wall wart with a simple transistor
arrays of several LEDs in series is a pretty cheap
"ballast" as such
things go. Yes it needs at least one or two resistors,
but they need not
be conducting all that current and creating heat.
My ideas may be a bit overdone,
Not overdone if you supply us with some schematics. I can
solder but I can't design the circuit
Find me a cheap supply of LEDs and I'll work on it. :-)
but I would like to
roughly regulate the
current to maintain constant output with age, temp, etc.
And to keep things kosher when one or more of the LEDs goes
That is pretty rare, which is why cities like them for traffic control.
Ever seen a burned out one in a traffic light? :-)
be kind of nice? Cheap, too, I suspect, compared to the
cost of the
LEDs. Traffic lights have made red and green into cheap
good blue is still a big problem, both in cost and maybe
10,000 K may still be a way off.
I see more problems working out mountings and attractive
housing. How do
we keep food from fouling them, etc.? Will algae quickly
grow on the
plastic lens and turn them off?
You could keep them above water, no?
I wouldn't be interested, having experienced the advantages of immersed
Gotta go chop some wood. Came home from So.CA to
frozen-up water lines,
Sorry to hear that. Beena there; mopped that.
Luckily no burst, just no flushing for an uncomfortable span. :-)
Finally cleared by this afternoon, but the
snow level is
down about 100' above the valley floor and dropping. Come
to think of
it, I'd like some lights that put out a *lot* of heat,
Think Incadescent, think heat
My reading lamp by the bed is a 100W halogen. Feels nice and toasty now,
but have to move it away in August.
Wright Huntley -- 760 872-3995 -- Rt. 001 Box K36, Bishop CA 93514
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