This circuit of the 70's uses transistors of the time. The circuit can amplify signals from 10 Hz to 100 kHz and modern equivalent components can be used. The circuit is from Ferranti.
This symmetrical power source for currents up to 1 A was found in a 1986 documentation, serving...
This circuit synthesizes the tick of a metronome with the speed controlled in RV1. The circuit is...
Found in Radio Electronics from the 90s, this circuit generates signals from 100 Hz to 1.5 kHz....