This version of triac control is from a 1968 documentation. The circuit uses components from the era that can be replaced with modern equivalents.
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...