ATX Bench Supply Question

Discussion in 'The Projects Forum' started by RayInMS, Dec 28, 2012.

  1. RayInMS

    Thread Starter Member

    Dec 12, 2012
    89
    1
    Hi all -

    I'm doing the ATX-to-bench supply conversion, and I have a question about current. Current ratings refer to the capabilities of the supply, not the actual output...correct? Meaning the supply is capable of delivering X amps to a circuit? I'm new to the hobby and have a general grasp of Ohm's Law etc., but I've been working with batteries and am new to bench supplies.

    I'm installing 1 amp fuses on all the outputs for some protection, but I'm worried that the supply will send too much juice to the stuff I'm working on (hobby circuits, none requiring more than 500 mA). As I understand it, the components of the circuit determine how much amperage is delivered...and that the power supply will only provide what is needed (e.g., the circuit will only take what it needs, and not all of the available amperage).

    Sorry for the dumb question. :D
     
  2. tracecom

    AAC Fanatic!

    Apr 16, 2010
    3,869
    1,393
    Your last paragraph is correct. Circuits will only pull the amount of current they are designed for, so having more current available than they require is a good thing. Think of the current available from the mains outlets on the wall; they can provide 15 or more amps, but you plug in a small radio that only requires 1 amp or less.
     
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  3. Dodgydave

    Distinguished Member

    Jun 22, 2012
    4,969
    744
    The current supplied is dependent on the load drawing the current, so if you connect a load that draws 500mA, then it will give out that, if you connect a load that needs 10Amps the psu will deliver that also,

    it will only give out what is required.
     
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  4. RayInMS

    Thread Starter Member

    Dec 12, 2012
    89
    1
    Thanks. I thought I had that right, but it's a little overwhelming when you're looking at that ATX and see a whopping 20+ amps at 5 volts.
     
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