Another power source
Hi Brietech,
Don't know what a H bridge is, but i have been intrigued by this article in Silicon chip, so much so that i looked up the datasheet for the Texas Instruments TL499a, found and ordered a few.
http://www.siliconchip.com.au/cms/A_100886/article.html
As BB says, +_ 9 is 18V from another reference point. According to the TL499a data sheet you should be able to get the 18V and few milliamps you want from 2 or 3 x AA batteries. Amazing. This chip also has a linear regulator for higher voltage input, so the batteries can be used as a battery backup. Should be just perfect for powering a picaxe at 5V.
I found the chip at futurelec.com, and they are only $1. An inductor, a few capacitors and resistors and you can get about 40mA.
I have a metal detector that takes 3x 9v batteries, so i'm hoping to use this chip and run the thing off three x AA batteries.
Good luck with your magnetoplasmastic drive. Didn't they have one of those in The Hunt for Red October?
Michael