This harmonic oscillator controlled by crystal was found in an American documentation of the 90's. The circuit uses transistors of the time. Current equivalents can be used.
This differential amplifier, found in a 1964 Electronic Design, has a gain of 30. The setting can be...
This mid-waveband wireless microphone was found in a Raytheon transistor manual from the 1960s. The...
This circuit is based on the bistable configuration, but with the difference that the values of...