This circuit for controlling high power in the AC network was found in a Motorola documentation from 1968. SCRs can be modern equivalents according to the load power.
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...