"DoN. Nichols" wrote:

On 2012-02-19, Michael A. Terrell wrote:

"DoN. Nichols" wrote:

On 2012-02-18, Michael A. Terrell ? wrote:
?
? "DoN. Nichols" wrote:

[ ... Ne-2 lamps ... ]

[ ... ]

Hmm ... you know that a commercial product had that. The
Non-Linear System's digital voltmeters used a series of stepper motors
to implement a Kelvi-Varley divider. Four digits, IIRC. Really noisy
with the sound-deadening cover off for test or repair. :-)


Today, you could use a couple rectangular LEDs per segment. You could
even change the color for out of range conditions.

Yes, those would be pretty good. Of course, they would be
*much* more expensive to make than the off-the-shelf 7-segment LED
readouts. (There was a *lot* of precision machining in that NLS readout
assembly. :-)


Which would be easy with a CNC machine. Can you imagine the problems
NCR had making their mechanical cash registers without CNC?


However -- they needed a lot more illumination than a NE-2
could create. They used the little flanged incandescent lamps of the
327 series. (I forget what the actual number was. 327 was 28V IIRC,
and 328 was 6V. They were common in aircraft indicators and such.)


And in legended indicator switches. I still have a few of both types
as spares.

Indeed so, as do I. Lovely little things. What would be nice
would be to get LEDs in the same package -- ideally with a built-in
bridge rectifier to make them happy with AC power. :-) Should last a
*lot* longer than the same lamps in a vibrating environment like an
aircraft cockpit.


LED replacements have been available for over 20 years, but they are
even more expensive than the lamps they replace.

--
You can't have a sense of humor, if you have no sense.