Found in a 1964 Electronic Design, this circuit makes use of period components. The components are from the time, and modern equivalents can be used.
This circuit simulates an inductor. Or operational amplifier of old type, but a configuration is...
This circuit for the logic control of the 555 in a power supply was found in the October 1989...
This traditional configuration from a 1980 publication shows how a reed relay is used to control a 240...