Building my first Arduino project and I would like to supply power to my relays and devices from something other than the arduino. I have an old lenovo AC adapter that outputs 20v at 4.5 amps. The regulator (round 1.5 inch barrel in the cord) on the AC adapter was frayed and sparking. I cut the regulator(?) off the cord and would like to replace it. Can anyone suggest a what part number I should replace it with?
Once i get the AC adapter back up and running I was planning on using a 7812 to provide 12v to some devices and then splitting that off with a 7805 for all the 5v devices. Will that work? Does that sound like a realistic plan? Thanks!