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.

Digital Potentiometer (CB12805E)
The resistance found between the R terminals of this circuit depends on the digital programming made at...
2 transistor radio (CB20517E)
This circuit with germanium transistors was found in documentation from the 50's. The transistors are...
Battery charger with current and voltage limiter (CB9537E)
This battery charger circuit was found in ancient American documentation. The components are...