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[email protected] krw@att.bizzzzzzzzzzzz is offline
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Default Why aren't many / most LED light bulbs dimmable?

On Sun, 26 Dec 2010 01:09:29 -0600, G. Morgan wrote:

wrote:

Resistors heat == inefficient

But the resistor will always be there. You are just making a bigger
resistor, the current will drop and the light will dim in a vary
linear way.
The voltage you drop across your resistor will be the same no matter
how big it is. That is not like a rheostat on an incandescent where
you are changing the voltage applied todrop the filament.


The voltage across the resistor *does* change. Also, P=I^2R.


How does the voltage change across a fixed circuit? I think
everyone here is talking about an Xmas tree lighting situation
(now), in a series arrangement.


He's talking about dimming LEDs, as in under-cabinet lighting.