1. We will be in Read Only mode (no new threads, replies, registration) starting at 9:00 EDT for a number of hours as we migrate the forums to upgraded software.

How to build PSU with 12v/5v/3.3

Discussion in 'The Projects Forum' started by MrYu, Jul 25, 2012.

  1. MrYu

    Thread Starter Member

    Sep 26, 2011
  2. R!f@@

    AAC Fanatic!

    Apr 2, 2009
    What for, a PC or for project testing?
  3. mcasale

    Senior Member

    Jul 18, 2011
    It would help if you gave more info about your application. How much current is required for each voltage? What are the tolerances for each supply?

    Why is there a battery? Do you require survival during momentary brown outs?

    The transformer selection is critical. It's output voltage will determine how much power each regulator dissipates under load.

    Power supplies are NOT brain-dead simple designs to do.
  4. #12


    Nov 30, 2010
    I did one of these yesterday. Here's the basic layout. Just leave out the "5.1 kit".
    Edit: This one uses a low dropout regulator. If you want to go old school, raise the transformer to 25.2 V center tapped (you can get 'em at Radio Shack).
    We await more details from you.
    Last edited: Jul 25, 2012
  5. BMorse

    AAC Fanatic!

    Sep 26, 2009
    A computer power supply will supply these and more.... plus it will only run you a few dollars :), spend less time and effort on the power supply and have more time to spend on projects to power off of it.