This circuit has the function of automating some type of equipment when a powerful transmitter is activated nearby. The circuit was found in a 1967 documentation.
This is an old test circuit for integrated TTL counters, feeding a Nixie tube, common at the time....
This old oscillator using germanium transistors has a high impedance headphone as inductor to...
This preamp with several inputs using germanium transistors from the time was found in Japanese...