Calculator displays

From: Don Maslin <>
Date: Mon May 11 23:51:27 1998

On Mon, 11 May 1998, Tony Duell wrote:

> > Yes, I remember those being used in the Electro Instruments and - I think -
> > Non Linear Systems digital voltmeters. You know, the stepping switch
> > based ones that really 'sang a tune' when in operation.
> Topic drift alert...
> Somewhere I have an article (including schematics) for making a 10 bit
> successive approximation A-D using relays and stepping switches. The null
> detector is one of those moving-coil polarised relays (which could be
> tripped by 50uA). It punches the data on a 5 level paper tape, I think.
> I've always wanted to try it. Maybe I'll have a go sometime...
> > By your later e-mail, you have that image form some website. Good, as it
> > would be almost impossible to make a reasonable ascii sketch of it. They
> > glow blue (what gas is that? argon?) and are viewed through a green filter.
> Is it a gas discharge or a fluorescent anode? The latter are often green/blue

I think gas discharge, as they have the mesh anode that you referred to
in another message.
> If it is a blue gas discharge, then the most likely gas is mercury
> vapour, I think.

OK, they are definitely blue.
                                                 - don
> -tony
    Don Maslin - Keeper of the Dina-SIG CP/M System Disk Archives
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Received on Mon May 11 1998 - 23:51:27 BST

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