> I'm looking for a schematic for a dual 12V @ 3A, 5V @ 3A power supply
> with battery backup and charging circuit (eventually). I have searched
> the web and have found nothing similar (only for sale, but I need to
> build it myself).

Google for data sheets and application notes for an LM350 regulator.
This can be adjusted to 5v and 12v at 3A (one for each circuit) .

Basic information and datasheets here

        http://www.national.com/pf/LM/LM350.html

        There are a number of application circuits in this datasheet that
directly
        address your requirement.


The LM317 is the 1 amp equivalent - there are more application notes around
for the 317 than the 350.

Datasheet         http://aes.sdsu.edu/documents/LM317-D.pdf



Then come back and ask more questions :-)


        Russell McMahon

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