They are cute, and have the usual colour more often seen in delicious Panaplex displays.
They were frequently seen in the background of 50s and 60s movies/TV. The good ones showed them performing some scientific/military job. The bad ones (e.g. excreble SF / cold war propaganda) used them as blinkenlights.
Anyway, feast your eyes here http://www.tnmoc.org/special-projects/harwell-dekatron-witch including a video of the computer being rebooted with some of its original designers. A shorter version is
ALSO a very interesting watch... So wait a minute. This thing... the Dekatrons themselves are the registers. So this prehistoric Turing-age machine... it actually used decimal-coded logic as opposed to binary-coded?
Yes, yes, and yes.
Clearly the pulses used to advance the register are binary;
Nope, they are simple analogue pulses. The input to one dekatron can be derived from another dekatron' s output.
but the register itself is inherently decimal (or, apparently, many more states are possible; it appears Russian-made tubes are available with many more "poles"), so it must be decimal, right?
Yup.
Interesting thing: Now that we're trying to make ever-larger SSDs... we're going back to that kind of logic... where each "bit" (cell), instead of having a binary state, can be one of 8 (TLC) or even 16 states (QLC) now dependent upon the voltage stored in a single cell.
Everything is analogue, except for photon counters and femtoamp circuits. In most cases the analogue voltage or current is
interpreted as a binary signal and then regenerated before being passed downstream.
Yes, that is an exaggeration, but not much of an exaggeration.
Of course that is still converted back & forth through a more traditional binary buffer;
That binary buffer is called an ADC
![Smiley :)](https://www.eevblog.com/forum/Smileys/default/xsmiley.gif.pagespeed.ic.R8GFI-pF6f.png)
but still... the idea of modern machines that "think" in something other than binary has always fascinated me.
Your next assignment is to design a circuit that divides a pulse train by 5 so that a 10MHz input becomes a 2MHz output. Your junkbox contains
three transistors, plus diodes, resistors and capacitors.
You will lose points if the circuit closely resembles that of a Tek 184 time mark generator.