Hi all - I'm looking to build a variable dc power supply (5VDC-12VDC) based on a wall wart. What type of wall wart should I buy? Also, a schematic would be great!

Scytheye

PS: If you know of a schematic based on a PC power supply - that would great as well (The PC power supply is an HP-145SNH by Dell and outputs +5VDC at 18A, -5VDC at 0.3A, +12VDC at 3A, and -12VDC at 0.3A.

 

Building you own switcher is a grand master grade project.

The wall wart for the 5 - 12 volt supply should output about 14 volts, and be able to supply more current than you need. Just get the data sheet on an LM317 variable regulator and build it.

 

Do it yourself (the schematic). It would be fun for you (in my point of view, of course - and gratifying)!

If you read the specs of the LM317, you can do what you ask. If you need help on something, feel free to ask (you might need an heatsink).