T3D Re: RGB LEDs

[Michael Kersenbrock <michaelk@xxxxxxxxxxxx>]

Tom Hubin wrote:

> Pulsing, as you suggest in your next response, can also be used. As long
> as the rep rate is greater than 30Hz so that you do not perceive the
> flicker. Tens and even hundreds of Kilohertz is no problem for LEDs.

Actually, pulsing the LED is an old trick for making the LED brighter
and/or lowering the current consumption.  One can pulse it at high
enough frequencies as not to see flicker (hundred Hz or faster,
more or less) with some duty cycle such that the absolute maximum current for
the diode isn't exceeded, and the average current is what you want.

The LED will appear brighter than the same LED being fed the same
average current (non-pulsed). Eyes tend to peak-detect so it's seen
as brighter.  Of course to have a net-gain in current savings, one
has to use a low-current pulsing circuit, and take care to keep things
efficient (not too hard nowdays).

Mike K.