This Texas Instruments circuit is from the 80's. However, it can be implemented with modern operating systems. The power supply must be symmetrical.
This step-down converter with 10 to 60 V input produces a 5 V output with a maximum current of 5...
Found in an old American documentation, this step has as input and output transformers coupling. Two...
This circuit was found in a 1963 magazine, but can still be easily assembled with some current...