TTL homebrew CPUs

Ed Thelen ed at ed-thelen.org
Fri Jul 13 00:22:03 CDT 2007


Drifting from TTL homebrew computers into NE-2 relaxation oscillators - 

The year Sputnik went up - October 1957 - I built a Sputnik oriented
   Christmas tree ornament for my sister.

The "earth" was 3" transparent plastic tube cylinder barely large enough 
  to hold a selenium rectifier, small electrolytic capacitor,
  47K  resistors and  disk capacitors.

The transparent tube orbit had three support tubes,
   and contained the seven NE-2 gas tubes.

I thought it cute but was disappointed that the start-up
  and operation was so unpredictable. Direction of rotation
  and number of satellites was variable.

But my sister was delighted, and has it to this day -
   but it now goes on the tree only when I visit.

Time has been  unkind. 
The gleaming  wires  have turned ugly black, 
  the plastic yellowed,  the lamp cord dried and cracked, 
  and I forget if it still works ... .



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