Black Iccy wrote:

On Sun, 28 Oct 2012 22:38:05 -0700, Jeff Liebermann wrote:


https://www.sparkfun.com/products/8799
Probably not big enough to see across a room, but still interesting.



I hear you Jeff. I know the LM dot/bar chips too.
All these things require another power supply to
run them. I'm after something "self-propelled" .

The ideal situation is to take the 200 W,
Step it up to 1,000,000 V and use the spearing arc
to get the barman to turn things down a notch.

Reverting: Just looking at some E-diagrams for
these car tacho's, some seem to have a double winding
as a designate sine/cosine measurement from the chips.
This implies we are still ultimately at an analog system.
step up transformer of some kind?

Jamie