Found in Ferranti's 1968 documentation, this circuit uses a Darlington photo transistor to drive a 12V relay. The circuit can be implemented with modern equivalent components.
Found in a Hands On Electronics from the 90s, this circuit can be easily assembled today, as the...
I found tis circuit in na old documentation from 1958. The circuit uses germanium transistor...
This is the basic configuration of a CMOS 4027 integrated circuit as a flip-flop. The circuit can...