Neon logic

From: Peter C. Wallace <>
Date: Fri Feb 28 09:35:01 2003

On Fri, 28 Feb 2003, William Donzelli wrote:

> > I'm fascinated by the idea of making counters, logic gates, and
> > memory elements using neon lamps, but repeated google searches reveal very,
> > very little hard information (other than there were such circuits).
> I seem to remember seeing some stuff about this in old trade magazines,
> like Proceedings of the IRE or Electronics. Check a good library (maybe
> on from a tech school).
> > Also, I've read a few pages on early calculators (such as the Anita) using
> > something similar to neon lamps for logic gates and ring counters, though
> > the pictures lead me to believe they are actually 4-lead gas triodes or
> > thyratrons of some kind. Do you know what these beaties actually were?
> I don't know, but frankly, I don't see why you would want to use gas
> triodes over regular triodes for low power logic. If anything, the long
> term instability of the gas tubes might be a problem (note that neon
> bulbs degrade quite obviously, but submini triodes last forever).

I've looked recently inside an Anita MK IV calculator and a doubt that you
would want to use that many tubes with heaters in that small a case...

The thyratons it uses are cold cathode and quite small. It also uses 1
Decatron tube...

> > Finally, I've repeatedly run across mention that neon device switching is
> > slow, but how slow are they?
> It depends on the tube. Some of the industrial gas tubes are indeed slow,
> but they have no need to go fast, controlling motors and relays and things.
> Some ring counters (Dekatrons) can go reasonably fast - 100 KHz is
> reasonable. Of course, most reasonable people would call 100 KHz slow.
> William Donzelli

Peter Wallace
Received on Fri Feb 28 2003 - 09:35:01 GMT

This archive was generated by hypermail 2.3.0 : Fri Oct 10 2014 - 23:35:57 BST