On Tue, 19 Jan 2010 10:28:56 -0700, Jim Thompson /Snicker wrote:

On Tue, 19 Jan 2010 12:10:28 -0500, "Charlie Smith"
wrote:

I will be building the PWM board and will simply test it. As you have
often
said, there is a reason why we put that one word promanently in our
aircraft.

"Experimental"?


Ignorance is bliss ?:-)

...Jim Thompson


Don't be so tough Jim. Ignorance is not a bad word. Its an entirely
curable condition. Stupid. Now that's incurable. And experimental doesn't
mean making an airplane the way the A-Team would; with a canvas, a couple
bamboo poles and duct tape. All it really means anymore is that the
airplane can be more modern than 1950's technology and you don't have to
auction off your first born. In the larger scheme of things, I don't see
instrument panel lights in the same arena as wing bolts. Let's try and keep
some perspective. Most of the suggestions made here would work just fine.
Just fuse the lights conservatively from the main buss and the very worst
that would happen is you would find yourself getting the flashlight from the
flight bag. And that happens more often than you might think.


Charlie


How many times have you been told that PWM'ing (without an inductor)
DOES NOT use any less power than the linear regulators that John
Fields and I have presented?

Really? Care to back that up with a LTspice simulation? Use Charlie Smith's
circuit or a near variant, steps of say 5% from 5% to 95% on time.

And PWM'ing creates EMI.
Yep.


Ignorance simply means "without knowledge"... not bad in itself... but
if you adhere to doing it your way when you've been told by experts
that there is no advantage, you graduate to stupid ;-)

...Jim Thompson