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.

Galvanometer amplifier (CB21651E)
Obtained from a 1967 documentation, this circuit uses transistors from the time. The galvanometer can be a...
Linear Ohmmeter (CB10685E)
The circuit we present was found in an English magazine from 1980, but it can be easily assembled, as...
Light Comparison (CB4363E)
I found this circuit in a 1974 magazine, but it can still be easily assembled because the...