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
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.