This circuit tests the offset current of an operational with the aid of an oscilloscope. The circuit is from an Electronic Design from the 90s.
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...