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Homework Help: Source transformations: confusing problem wording

  1. Sep 26, 2013 #1
    1. The problem statement, all variables and given/known data

    A certain practical dc voltage source can provide a current of 10.5 A when it is (momentarily) short- circuited, and can provide of 30 W to a 20 Ω load. Find the open-circuit voltage

    2. Relevant equations


    3. The attempt at a solution

    Well I'm pretty sure that the current entering the resistor load would have to be √(3/2), but I'm not sure exactly what to do from there. I don't quite understand what is meant by the 10.5 A when short-circuited statement. Like would that be the current through the source resistance?
  2. jcsd
  3. Sep 27, 2013 #2


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  4. Sep 27, 2013 #3


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    Staff: Mentor

    Yes on both counts. If the power source's output is shorted, the internal source resistance will be the only thing limiting the current.
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