Calculator displays

From: Don Maslin <>
Date: Mon May 11 14:11:15 1998

On Mon, 11 May 1998 wrote:

> Many thanks to all who replied about calculator displays. The general
> consensus seems to be that it was probably a Sharp EL9, an early and
> large hand-held calc (I'm sure it was larger than my hand, but never
> mind) from the early 1970s.

Well, that depends on the size of your hand. To be more precise, it is
4" wide, 6.375" long and somewhat wedge shaped with the taller end at
2.75" and the shorter (keyboard) end being 1.75". Probably weighs 1.5#
without 6 AA size NiCads.

> To clear up a few misconceptions:
> It was not a Nixie tube machine. I have a nixie tube calc and a nixie
> tube voltmeter, so I know what those are. Apart from the trademark
> issues, I regard Nixie tubes as being ones in which you have an
> electrode for each _character_ rather than each segment. Usually
> digits, but as Tim pointed out, other symbols were available.
> It was not a starburst display. I have seen 14 segment and 16 segment
> versions, but these are still based on straight lines, not curves, and
> the numerals are still the good old 7-segment ugly ones.
> It was also not the display I have in my other digital voltmeter
> (Dynamco, I think) which has as digits a multilayer Perspex sandwich.
> Each perspex layer has a dot pattern for a character drilled in it; you
> light up a character by illuminating the edge of the appropriate perspex
> wafer, and total internal reflection confines the light to that wafer,
> thus lighting up the dot pattern of only the one character. Neat.

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.

> I shall have a look at the website someone mentioned - thanks.
> But meanwhile, can someone who has a Sharp please e-mail me with a brief
> description of the segments of this 8-or-9-segment display and which
> ones light up for which digits.

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.

                                                 - don
> Many thanks.
> (A bit of background:
> Talking to my mother about watches, she said she never liked digital
> watches because she found 7-segment characters hard to read. I
> remembered this Sharp system and decided to try and find out a bit more.
> I wonder if it would be possible to revive it for LCDs and things - I
> still think it is much more readable than 7 seg.)
> Philip.
Received on Mon May 11 1998 - 14:11:15 BST

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