This circuit is from 1985 documentation. The integrated circuit is not very common today, but modifications can be made leading to a project with current integrated circuits.
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...