neon glow lamps (was TTL homebrew CPUs)
jim at g1jbg.co.uk
Thu Jul 12 15:35:31 CDT 2007
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
> > > 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.
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