Scrap all of those ideas.
FREE switching power supplies are being thrown into the junk yard across the globe: ATX PSU from ancient PCs.
You can go to YouTube for any number of videos posted up by hobbyists.
All ATX systems are sophisticated enough to give you sweet DC voltages with trivial ripple.
+3.3 VDC
+5.0 VDC
+12. VDC
Even negative voltages:
-5.0 VDC
-12. VDC
And these boxes are being placed at the curb every day of the week -- everywhere -- FREE.
Just troll through CraigsList or call around for 'e-waste' or some such.
Because of the basic (DC) voltages provided, it's possible to straddle them to derive difference voltages:
+12. VDC minus +5.0 VDC = +7.0 VDC ===> and so forth.
The provided voltages are EXACTLY those required by hobbyists for all digital circuits.
Because of industry standards, these PSU are also surprisingly efficient -- WAY superior to ancient solid state junk. There's absolutely no comparison.
AND, these PSU are much safer to toy with. They're totally enclosed and have their own fan and fuses.
You can't beat them with a stick!
