[SML] Dummy load resistor?

[Dan Sheehan]

The resistance of a tungsten incandescent lamp filament
changes roughly  10:1  from hot to cold.

A 40W lamp at 120 V is passing 1/3A,
 so its hot R is ~ 360 ohm, so cold R could be estimated at ~ 36 ohm.
I just measured one, got ~ 27 ohm (cellar workshop, below normal room temp)

What level do you need to run the practical at,
and how long does it stay on for ?

On Thu, May 3, 2018 at 12:37 PM, Jon Ares via Stagecraft <
stagecraft at theatrical.net> wrote:

> Howdy folks....   I occasionally come to the challenge of using an LED
> practical on stage (like a light bulb) and I run a dummy load
> incandescent on the same dimmer when possible.... but sometimes, like
> now, I don't have a reasonable, practical way to do that, as I can't
> have a visible incandescent bulb visible anywhere near the "open air"
> practical - and it's not... practical... to run a dummy load bulb 50+
> feet offstage...
>
> Wouldn't it be possible to just wire in an appropriate-sized resistor?
>  I know it would get warm, but I've got lots of open air (don't need
> to enclose the resistor) - but not finding any definitive info online.
> Lots of queries from people trying to get their kitchen LED cans to
> work, and the responses are usually "Why don't you just buy a dimmer
> switch rated for LEDS?"  Not helpful in my situation....
>
> Thoughts?  What size resistor would be necessary to fake a few watts?
>
> --
> Jon Ares
> www.arescreative.com
>
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-- 
...Dan Sheehan
Fixer of things that break
TD Walpole (MA) Footlighters
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