Wanted: vacuum tube logic circuits - test-drb@ccmp.vtda.org

30 Aug 2008

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Subject: Re: Wanted: vacuum tube logic circuits
   From: "bfranchuk at jetnet.ab.ca" <bfranchuk at jetnet.ab.ca>
   Date: Sat, 30 Aug 2008 17:57:30 -0600
     To: General Discussion: On-Topic and Off-Topic Posts <cctalk at
classiccmp.org>

William Blair wrote:
  Actually, 24 of the 41 types of space charge
tubes had filament currents ranging from only 150 - 200 mA.  The 12DL8 had the highest at
550 mA.
    I remember reading somewhere on the web about the high current. I did not dig
any more.
As for pencil tubes ... I suspect most of them where for WWII use and the general public
did not
know about them till after transistors made their impact.

 Not quite.

Tthere were several forms of pencil tubes and the smaller ones were appearing in hearing 
aids and others small devices just after the war.

The ones that were less known were the hyper rugged ones used in the VT fuses 
and those were mostly secret.

I have a dozen or more of the pencil types some fo the 1AD4 class with 1.5V filiments
and the other the harder and more rugged types with 6.3V heaters.  I"ve built gear 
around both.

Allison