This circuit was suggested by National Semiconductor and is present elsewhere on this site. The LM2575 is not very common today and should be mounted on a heatsink.
Found in American documentation from the 1980s, this circuit can be designed with equivalent...
The 4028 CMOS IC not only contains the complete decade counter, but also the 7-segment decoder...
We found this circuit in an American 1980s documentation. The circuit can be assembled with modern...