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.
The battery charger suggested in the figure has its current limited by resistor R1. This component can...
The operation of this circuit is not common today, but equivalents can be experienced. The circuit is...
This circuit generates various types of sounds and can be used as a toy. The circuit is from Radio...