From: John Larkin
Subject: Re: Digital divide by ten, 1949 style
Date: Sun, 15 Sep 2002 12:25:44 -0700
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On 15 Sep 2002 09:46:32 -0700, firstname.lastname@example.org (Tim Shoppa)
>In a recent thread on sci.electronics.design, we explored some approaches
>to divide-by-ten without using IC's. (Go to http://groups.google.com/ and
>search for "Decade counter without IC's"). Here's an approach I found
>in Vol. 19 of the Radiation Laboratory Series, _Waveforms_:
>They do it with just ten tubes, and the output is BCD on 4 neon bulbs.
>Comments on similar counters would lead me to believe that the design is
>good to a few MHz.
>Maybe they do cheat a little with respect to the previous thread; is a
>dual triode the 1949 equivalent of an IC? :-)
HP's first counters used tubes, and the readout was ten neons stacked
vertically for each digit. They also used to sell the decade counter
module with readout as a standalone product. It had four dual triodes
and a lot of Rs and Cs. I've got the schematic around here
The classic "Pulse and Digital Circuits" (Millman and Taub, 1956) has
a couple of 4-tube decade counter circuits, but not the one with the
tricky resistor matrix that drives the ten neons.
Ref: A Four-Tube Decade Counter, Potter, Electronics Mag, June 1944.