Thread: DC power supply...HELPPPPPP

Originally Posted by walid_bmw

because, theoretically, doesnt the ac power supply take the 110Ac, convert it to 12v dc, then 5v dc then 3.3 v dc?

Yes, kinda. The 5v and 3.3v is not usually derived from the 12v. They usually have separate secondary windings on the main switching transformer.

Originally Posted by walid_bmw

so what i could do is wire the 12v regulator to the output of the transformer that changes the ac to 12v dc thereby canceling out that transformer??

Nope. The transformer doesn't change 110ac to 12 dc. The combination of the primary bridge rectifier, primary switching transistors, main transformer, rectifiers, and the associated feedback loop converts the 110ac to the DC supply your PC needs. There is a lot more to a power supply than a transfomer, as I'm sure you know (having had it apart). The regulator loop in these supplies is a switching feedback loop that controls the primary switching transistors on the transformer. Do some research on transfomers and switched mode power supplies.

Originally Posted by walid_bmw

thanks a lot and please dont laugh....

Ok


Rob

also bear in mind you might need to get a -12v and -5v.

one freindly advice after reading your post ... DONT play with the A/c power supply ... it can burn.

The modification for the a/c PSu to work in car is way to complexed.. so just go the dc- dc way you will be more than happy you did....

Good luck
Mastero