20 Apr
2005
20 Apr
'05
7:50 p.m.
On Thu, 21 Apr 2005 00:07:17 +0100 (BST)
ard at p850ug1.demon.co.uk (Tony Duell) wrote:
My 'EPROM Eraser' uses a multi-element tube. It's actually an old quack
medical device from the 1950's. It's a big 'cold quartz' UV lamp, and
has a high voltage power supply in the base that uses one of the 'newer'
versions of a multifunction tube, the 117L7GT, which is a tube with a
117 volt filament and (I believe) several different tube stages.
Probably the _last_ versions of multifunction vacuum tubes were the
'Compactron' tubes, specifically designed multi-element tubes used in
the 60's and 70's in sets sets designed to use with fewer tubes, i.e.
portable tube-type televisions. Compactrons were in an envelope similar
in shape to the common 7 and 9 pin mini tubes, but bigger with (if I
recall correctly) 12 pins.
Before anybody comments with alarm, yes, I know that the EPROM eraser is
VERY dangerous (totally unshielded and a fairly powerful light source)
but it's constructed in such a way that the light source can be
positioned directly over a conductive mat of EPROMs so no light escapes,
which is how I use it. I'm not sure what medical claims were made
regarding it, but I did once find it 'displayed' on a website of
historical Quack Medical devices. I guess you could do 'therapy' like
staring into the bright blue quartz tube to go blind or something...
If things had
worked out differently we might be using
ultraminiature electron tubes. Imagine! An entire flipflop in one
package!
I nthe 1920's, Lowe (in Germany) made a radio receiver which consisted
of a tuend ciruit, headphones, batteries, and a single glass envelope.
That contained 3 triodes and all the R's and C's.
The idea did not catch on. The single glass device was expensive, and
if any part failed you ad to replace the whole thing. Other radios
were much cheaper to repair.
A flip-flop valve would certainly be possible.
-tony