18 Jun
2006
18 Jun
'06
12:46 a.m.
On 6/17/2006 at 11:03 PM ard at p850ug1.demon.co.uk wrote:
I think one of the early computers (EDSAC?) used a
matrix of neons and a
photomultipler as one of the ROMs. They had to 'flash' a light on the
matrix jut before each read (and gate out the resulting pulse from the PM
tube) to ensure a neon in the matrix would strike when required.
I still have a neon "night light" in my shop that's just decrepit enough
that it comes on only during the daytime or when I turn the overhead lights
on. This avalanche effect of gas devices can come in very handy when used
for something like a PM tube.
(Point of curiosity: In British English, when is a tube a valve? You
fellows don't talk about "Cathode Ray Valves" do you? Is a photomultiplier
tube a "valve"? How about a TWT?)
Cheers,
Chuck