Keith Packard [Fri, 26 Dec 2014 03:30:52 +0000 (19:30 -0800)]
Fix D2 goof-up. Adjust value silk positions
Oops. When sticking the silk text on the back, I must have rotated D2
accidentally, which puts the pads in the wrong location. I've moved
them back, but the first build is gonna be awkward.
Also moved all of the component value text around to make it usable.
Keith Packard [Wed, 24 Dec 2014 08:07:54 +0000 (00:07 -0800)]
Add a 20V darlington source. Switch to STM32F042 (Schematic changes only)
This provides *both* the low current zener noise source and a new 20V
darlington noise source to see which one works better.
The low current zener source has been updated to filter the input
power and provide for both low-pass filtering and configurable gain in
both op-amp stages to allow for more experimentation.