[GreenKeys] Teletype power supply design

[Ralph Mowery]

----- Original Message ----- 
From: "John Nagle" <nagle at animats.com>
To: <greenkeys at mailman.qth.net>
Sent: Saturday, April 18, 2009 12:58 PM
Subject: [GreenKeys] Teletype power supply design


    As a design exercise, I've been building SPICE models of possible
switching power supplies for Model 15 Teletypes.  The idea is to get
rid of the bulky and hard to find 120VDC supply and inefficient load 
resistor.

&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

While it might be a good exercise, the old type is almost fool proof.  Just 
a couple of components.  Transformer, diode, capacitor and resistor.
  It will still be interisting if you can find a way to hit the coils with a 
large enough pulse to activate them and then drop the voltage to a very low 
value.