The other day I built this power supply out of components I had lying around. In particular I had this enclosure sitting on the shelf for years now and wanted to finally put it to use and also a toroidal transformer I also had sitting in the shelf.
Unfortunately I didn’t take any pictures while building it only after the fact.
Here is the schematic, fairly standard and self-explanatory, it uses a 2N3055 transistor and a Zener diode. Though I changed the smoothing capacitor for an even higher valued one on the actual build.