We found this circuit in a 1967 American documentation. The diodes are general-purpose and the input frequency can be between 80 and 800 Hz.
This circuit is from 1997 documentation, based on the well-known integrated circuit 555 and 4017....
This circuit is from 1980 documentation. We can exchange the BC177 for a BC557 and the TIP41 must...
From different input voltages V, it is possible to reduce the voltage to several fixed values...