16 Dec
2008
16 Dec
'08
9:55 a.m.
>>>> "Christian" == Christian
Corti <cc at informatik.uni-stuttgart.de> writes:
Christian> On Mon, 15 Dec 2008, Tony Duell wrote:
> How did they work? I rmember seeing (and alas
failing to obtain)
> an partically mechanical digital voltmeter. The circuitry was a
> servo
Christian> We have an old DVM from 1960, a Solartron LM 902. It has a
Christian> few tubes, a lot of Germanium transistors and also a lot
Christian> of relais for the display. The display consists of four
Christian> digits, which are big black blocks with twelve light bulbs
Christian> in a 3x4 matrix (ten digits, decimal point and red
Christian> background illumination for *positive* numbers) and a mask
Christian> for each digit. The light passing the mask is then
Christian> projected onto the front of the digit unit.
Those were the best quality (by far) numeric display devices ever
made. Unfortunately, also rather bulky. I think I still have a set
of 3 somewhere.
They were also used in some computers; the CDC 1604 console is full of
them.
paul