This circuit was found in the June 1982 issue of Radio Electronics magazine. It provides reference voltages for calibrating instruments such as oscilloscopes.
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...