wrote:
On Wed, 10 Sep 2008 00:46:23 +0000 (UTC), (Don
Klipstein) wrote:


In article , wrote:

On Tue, 09 Sep 2008 16:58:09 -0400, Jeff Wisnia
wrote:


wrote:


On Tue, 09 Sep 2008 13:42:39 -0400, Jeff Wisnia
wrote:

SNIP to edit for space

And dimable LEDs ought to be a no brainer.

Jeff


Not nearly as easily accomplished as you think, Jeff.


I dunnno, you may be correct. This supplier says it can be a so-so thing
when using conventional pulse width varying dimmers.

http://www.besthomeledlighting.com/faqs

But I'm reasonably sure that compatible dimmers will become available
when LED bulbs really take off.

Jeff

The most reliable dimming at this point is to have an array of LED's
and make it so you can use varying portions of the array.

The delta from no light to full brightness is very short for LED's.
That makes effective dimming tricky at best.

Where do you get that idea?

- Don Klipstein )


Well, Don, I think you'll find that when you try to use a dimmer with
an LED, it's far from linear. You'll have to turn the dimmer up about
half way, and then the LED will come on, but it will not be dim, it
will start out at about half brightness. Then moving the dimmer a very
short amount (with a very steady and precise hand) you will go from
that stage to full brightness.

Try it, and you'll see.

I believe you on that, because commonly available dimmers aren't exactly
compatible with the relatively low currents drawn by LED bulbs,
particularly when you're trying to run them "dimmed down".

But, I still feel it won't take rocket scientists to design dimmers
which DO work well with LED bulbs. But then, those dimmers might not
work too well with incandescents. G

I remember visiting the Hammond Castle in Gloucester, Massachusetts and
seeing good sized wall mounted variacs used for light bulb dimming in
some of the rooms in that gorgeous place.

http://en.wikipedia.org/wiki/John_Hays_Hammond_Jr.

and

http://community-2.webtv.net/JohnDandola/HammondCastle/

Jeff

--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
The speed of light is 1.8*10^12 furlongs per fortnight.