neon glow lamps (was TTL homebrew CPUs)

[Jim Beacon]

From: "Tony Duell" <ard at p850ug1.demon.co.uk>

> >
> > > At one time one could get three terminal neon lamps. These could be
> > > used for many logic functions reliably since they always had on
electrode
> > > with ionized gas on it.
> >
> > You still can. They are called Krytrons, are expensive, DAMN fast, and
> > are export controlled.
>
> There were also some sloower ones called 'Trigger Tubes', which AFAIK
> have no export restrictions (they are not suitable for that use, far too
> slow) but can be used for logic, etc.
>
You can also look out for tetrode thyratrons - these have an extra electrode
that can be used to control the trigger point to some extent. The are
available as heated and cold cathode versions.

Jim.