Huge scale, working model of a 555 timer chip using vacuum tubes

[nixxon]

I was impressed by this guy:

https://youtu.be/bjAlzA4Cyys

[schmitt trigger]

I am beyond impressed!

Having said this, I once saw an analog TV sync generator made exclusively from tubes. It occupied a refrigerator sized rack.

[daqq]

Awesome build!

Datasheet:

Power consumption: YES

[T3sl4co1l]

Datasheet:

Power consumption: YES

A reminder that the WOM specified heater power.

Another "misuse" of tubes, I did this a long ass time ago:
https://www.seventransistorlabs.com/tmoranwms/Elec_Compound2.html
(It's kind of serial and doesn't have a table of contents, just scroll down a few headings to see the final form, or read the background leading up to it if you like.)

PWM in the low 100kHz range is quite feasible from tubes, and a final plate efficiency around 80% is achievable.  Mind, overall efficiency still tops out around 50-60% from all the heater power, and bias drawn by everything else.  Not having complementary devices really sucks for slew rate and power consumption (drivers and logic basically have to be "NMOS", as it were), but heaters consume about as much as bias so it's not like there's a whole lot to save either way.

Note that the above is a sort of "class D-A".  It has a load resistor to carry bias current to the output, so while the switching has high plate efficiency, the overall output efficiency is normal class A.  "Neat", huh?

More recently I made this,

https://imgur.com/gallery/OF4jAxh


Schematic: https://www.seventransistorlabs.com/Images/Tube_Shift_Register.pdf

Tim

[TimFox]

In my entry years ago to the Signetics WOM design competition, I used 12AT7 triodes as a convenient interface from standard TTL (into the triode cathode) to a signal impossible to ignore.

[schmitt trigger]

One of the advantages of vacuum state electronics, is that they can be abused significantly without damage.

You see the plate glowing cherry red? Unplug it, let it cool down, and then proceed to troubleshoot. There will be the usual discolored resistor, which can be easily replaced, but most times every thing else survives.