This switched regulator configuration was found in Motorola's 1969 documentation. The integrated circuit is from that time and is difficult to obtain today.
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...