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.

PH meter (CB5324E)
This circuit is from an 80's documentation. The circuit makes use of a component of the era, the...
FM Receiver via Power Grid (CIR25197E)
Unlike the previous one, this circuit is intended for the reception of frequency modulated signals...
4 Channel Mixer (CB4921E)
This circuit is from an old National Semiconductor component manual. The circuit can be...