
A Mechanical Neon Oscilloscope - segfaultbuserr
https://www.novioljourneys.com/?p=475
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kens
IBM's 1402 card reader (1959) used something similar to diagnose timing
issues. The "dynamic timer" consisted of a spinning neon bulb that could be
connected to various signals in the card reader. When the signal was
activated, the bulb would illuminate, at a particular rotational angle. By
checking the position of the illuminated bulb against the angle scale, timings
could be checked.

For instance, it was critical that each row of punched holes in a card passed
under the brushes at the right time for the computer to read the values. The
dynamic timer would show 12 orange lines in a circle, indicating when each
hole was being read. If these lines were in the wrong position, the brushes
were adjusted until the timing was right.

You can see it in action halfway down my page about the card reader:
[http://www.righto.com/2018/02/repairing-card-reader-
for-1960...](http://www.righto.com/2018/02/repairing-card-reader-
for-1960s.html)

~~~
Animats
That rotary form of timing indicator was quite common. It showed up as an
automobile spark timing indicator used in repair shops, and in fathometers for
boats.

~~~
jhallenworld
The strobe scope version is still available:

[https://www.harborfreight.com/timing-light-with-
advance-4096...](https://www.harborfreight.com/timing-light-with-
advance-40963.html)

And I remember seeing a few of the rotary fishfinders / depth sounders still
in use in the 1980s:

[https://www.ebay.com/i/322412202248?chn=ps&norover=1&mkevt=1...](https://www.ebay.com/i/322412202248?chn=ps&norover=1&mkevt=1&mkrid=711-117182-37290-0&mkcid=2&itemid=322412202248&targetid=915850928613&device=c&mktype=pla&googleloc=9002077&poi=&campaignid=9338046851&mkgroupid=94993845019&rlsatarget=pla-915850928613&abcId=1139336&merchantid=6296724&gclid=CjwKCAjwltH3BRB6EiwAhj0IUF2l-GY9A9y79k8kF83-JvzOR-
qew2I3mqtLDS-CtBlaU3eIEY26rBoC0moQAvD_BwE)

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userbinator
_Imagine taking a repetitive voltage measurement at a predetermined time
interval and then graphing the results on a piece of paper._

Such devices actually existed and were common in the late 19th century ---
they were called oscillographs. The first few pages of this 1915 book have
some details on these devices, including the one in the article:

[https://archive.org/details/wirelesstelegrap00zennrich](https://archive.org/details/wirelesstelegrap00zennrich)

~~~
plafl
I don't know why but I was not expecting such an old book to be so richly
illustrated and with such a nice typography. Explanations look very clear too.

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peter_d_sherman
>"An oscilloscope is a time dependent voltmeter. It displays the change of
voltage over a period of time."

[...]

>"The tube used is similar to the familiar neon lamp that many an indicator or
night light was made from. The difference is the electrodes are in a line
rather than parallel." [...] "If you were to connect this to an alternating
current source, the appearance would be two glowing areas at each electrode.
_To the naked eye, this would appear constant_. Just like your night light.
Now if you could effectively increase your visual shutter speed so to speak,
you could catch the increasing amount of glow…followed by the decrease…and
then the increase upon the other electrode and so forth…..all within the 60Hz
line frequency applied to it."

In other words, something which is, in actuality, _oscillating_ \-- is
_appearing solid to the eye of the observer_ , because the eye lacks the frame
rate to observe the oscillation unaided...

I wonder, in how many other diverse areas of Physics, this same principle
might also exist...

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Daub
This is not a million miles away from Kelvin's Mirror Galvanometer (yes, that
Kelvin, after whom the Kelvin was named).

[https://en.wikipedia.org/wiki/Mirror_galvanometer](https://en.wikipedia.org/wiki/Mirror_galvanometer)

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Luc
This appears to be a sort of Magic Eye?
[https://en.wikipedia.org/wiki/Magic_eye_tube](https://en.wikipedia.org/wiki/Magic_eye_tube)

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adammunich
You can make a modern one of these with the Russian NOS long neon indicator
tubes.

~~~
jcims
Would be cool as an analog visualization for a stereo (with tube amps of
course).

