Neon logic

From: ben franchuk <>
Date: Fri Feb 28 00:13:00 2003

Robert Nansel wrote:
> I came across reference to a file, LAMP.ZIP, you posted briefly for the
> Classic Computer list back in '99. Would it be possible for me to get this
> file? 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).

Yes you can. I had a old electronic magazine* around years 1960 to 1962
that had such a beast.Alas the box I had my old magizines in got wet. :(
They switch the same way as a tunnel diode switches, using negitive
resistance and brute force. Inputs are capacitor coupled if I remember
right with diode logic for gating logic.

> 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?

They had decade counters but I don't have any links handy. Nixie tubes
are nice too.

> Finally, I've repeatedly run across mention that neon device switching is
> slow, but how slow are they?

I think 1000 cycles per second do to RC time constants. Any how
don't use neon bulbs with a built in dropping resistor. Paint
the bulb black to prevent light from triggering the devices.
Cosmic rays may do that too.

> You assistance is appreciated!
* those days magazines had few ads and profesional
Received on Fri Feb 28 2003 - 00:13:00 GMT

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