[GreenKeys] Model 14/15 Selector magnet inductance

[John Nagle]

    What's the actual inductance of the selector magnet on a
Model 15 and a Model 14? Are they the same?

    I've been working on a new driver board for 60mA
Teletype machines, and while it works on one Model 15
I have, it doesn't work on two different Model 14 machines.
The board works by charging up a 1uf capacitor to 120V
during SPACE, using a custom switching power supply
powered from a USB port. On transition to MARK,
the capacitor is dumped into the selector magnet,
and then a 12V supply provides sustain current.

Technical details of the new board at

https://github.com/John-Nagle/ttyloopdriver/

Scope trace of current and voltage into selector magnet:

https://github.com/John-Nagle/ttyloopdriver/issues/4


			John Nagle