Schematics of Atanasoff-Berry Computer logic circuits? - test-drb@ccmp.vtda.org

21 Aug 2008

...
   I'm not very familiar with vacuum tube circuit
design, but I
  have a PDF copy of the 1952 USAF technical order TO16-1-255
  "Basic Theory and Application of Electron Tubes" which looks
  like it might be sufficient. 

 Is that on line, or could you post it?   
I found it on an excellent vacuum tube resource page intended for audio amp builders, but
I can't find that specific page right now nor will a google search for that title and
with filetype:pdf result in proper hits, so I've uploaded the 16.6MB pdf here:

http://tinyurl.com/5dh946

You can review the entire document on-line.  Just click on the tiny "download"
icon above the preview to download it.  You've got to register to download from this
site, but it's free, doesn't result in any spam and is well worth it.  I've
found lots of interesting tech stuff there over time.

...
  Logic circuits are DC coupled, though, unlike audio
 amplifiers.  So the shift in operating point from the plate
 voltage change (or, for that matter, from a change in vacuum tube
 type, if you're doing that) probably means you'd have to change all
 the coupling resistors.  
Man, do I know that now.  I posted my comment before I'd fully digested the ABC web
page.  A multi-stage direct coupled vacuum tube circuit.  Fun.