11 May
1998
11 May
'98
4:51 p.m.
On Mon, 11 May 1998, Tony Duell wrote:
I think gas discharge, as they have the mesh anode that you referred to
in another message.
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 If it is a blue gas discharge, then the most likely
gas is mercury
vapour, I think.
OK, they are definitely blue.
- don
-tony
donm(a)cts.com
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