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Thread: DC power supply...HELPPPPPP

  1. #1
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    DC power supply...HELPPPPPP

    hi, im kinda new to this thing, just a small question on power supplys,

    i took appart my ac power supply off my pentium three and burnt it out,
    basically my question is , i bought a 12v voltage regulator so that i can stabilize my car's voltage to 12v, is it possible to use this to power my standard home pc? because, theoretically, doesnt the ac power supply take the 110Ac, convert it to 12v dc, then 5v dc then 3.3 v dc? 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?? HELP ME hehehhehe

    thanks a lot and please dont laugh....

  2. #2
    Raw Wave Rob Withey's Avatar
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    Quote 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.

    Quote 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.

    Quote Originally Posted by walid_bmw
    thanks a lot and please dont laugh....
    Ok


    Rob
    Old Systems retired due to new car
    New system at design/prototype stage on BeagleBoard.

  3. #3
    Confusion Master
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    also bear in mind you might need to get a -12v and -5v.

  4. #4
    FLAC Mastero's Avatar
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    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

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