Relaxation oscillator using a Thyratron (T426E)

This oscillating circuit for a frequency of 588 KHz was found in a book on electronic designs with modern tubes.

Bistable Sonic Relay (CB18272E)
With the configuration shown in the figure, we have the relay being activated when the microphone picks...
Pulse Generator (CB18236E)
This TTL generator that can function as a control shield or external clock for microcontrollers was found in...
Absolute Value Circuit (CB19719E)
The OP07 operational amplifier is not common today, as the circuit is from an old European manual....