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PC Power supply question...

Discussion in 'Electronic Basics' started by J Shrum, Mar 16, 2005.

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  1. J Shrum

    J Shrum Guest

    I've been using a 250W PC power supply as a bench supply.
    The ratings are on the label stating 12V - 7.5A surge.
    So if 7.5A is the absolute max, what would I expect the RMS to be? I'm
    running it into a flyback w/ a primary resistance of like 1ohm... I assume
    I'll have to throw a high wattage resistor in there to bring down the
    current through the primary, but what is the most that I can *safely* draw
    from this supply @ 12v.


  2. Tom Biasi

    Tom Biasi Guest

    Hi Jim,
    Usually the PS units have a maximum rating and a rating for each supply
    I haven't seen a 'surge' rating on a PC supply only a maximum output.
    Since you are using only the 12 V. section you would need to respect the
    rating for that section.
    If indeed your unit specs a surge then the continuous will be less than
    Since 12 V. with a 1 ohm load draws 12 Amps continuous, I think that we can
    *safely* say you are exceeding the limits of the PS :)
    A 7.5 A. surge could be 5A continuous or less.
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