DIYbanter - View Single Post - Why aren't many / most LED light bulbs dimmable?

G. Morgan[_6_]

z 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.