This circuit, found in a 1964 US documentation, consists of a selective amplifier that lets only 10 Hz pass around a 400 Hz center frequency with the indicated components.
This is a typical source of the time (1989) using the well-known regulator integrated circuit 723....
Found in American documentation from 1964, this circuit uses transistors from that time, which are not...
In the circuit of the figure, we have an application different from 4093. The astable...