[TR] gas gauge and voltage regulators

[Randall]

> Electronics is polarity sensitive although an electronic 
> stabilizer (regulator) can be designed to work with wither 
> polarity by including a full wave bridge and retuning the 
> circuit to compensate,

Hmm, maybe I'm missing something.  Seems to me that a full wave bridge wouldn't do, because the senders have to return to chassis
ground.  The only way I can see to implement this would be basically two complete regulator circuits with steering diodes so only
one is functional.  

Lots easier to just use a circuit that matches the car polarity, which is what the vendors do.  Eg Moss sells 131-555 for negative
ground, and 131-556 for positive.

It's also pretty easy to build one for yourself.  I used the can from an old stabilizer (with bad contacts) similar to what's shown
here
<http://bob_skelly.home.comcast.net/~bob_skelly/voltageStabilizer/voltageStabilizer.html>
But there's no reason you have to use the can, it's just a convenient package (with terminals).

If you want positive ground instead of negative, use a 7910 instead of the 7810, and switch the polarity of the capacitors.

-- Randall