To Jim Weir

Stealth Pilot wrote:
On Fri, 08 Jan 2010 16:54:14 -0800, Bug Dout
wrote:

Stealth Pilot writes:

charlie, assuming that you are using a 12 volt bus, all you need to do
to use an LED is put a 680ohm resistor in series with it.

Huh? You can't generalize about LEDs like that! There are many different
LEDs with different electrical characteristics. Given the OP's post,
you can't even state that a simple resistor is what he wants; he may
want variable lighting, in which case a potentiometer is what's needed.


I can state what I like. it is a free society.
what I wrote works for me.
ymmv
Stealth Pilot


Quite so. Moreover, the idea of providing an individual series resistor
to pass about 20 mA works for a good variety of LEDs.
Focussing on the desire to dim a LED, there is no reason (that I know)
not to reduce the current. This has the great advantage over pulse width
modulation that it does not kick up radio interference. There are LED
drive chips on offer now that might suit....

Brian W