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Thermal Energy Dissipated in a Resistor in AC vs DC

  1. Nov 7, 2009 #1
    1. The problem statement, all variables and given/known data
    What direct current will produce the same amount of thermal energy, in a particular resistor, as an alternating current that has a maximum value of 2.60 A?

    2. Relevant equations

    3. The attempt at a solution
    A DC would dissipate a constant amount of thermal energy in a resistor. An AC would dissipate a varying amount, but oscillating, so there would be an average. Couldn't I just say that since I know that current in an AC circuit oscillates as a sine wave, that the "average current" would just be half the amplitude, and so that over a period of time that is a multiple of the period of oscillation, a DC of half of the maximum value of current for the AC would have dissipated the same amount of thermal energy as the AC?
  2. jcsd
  3. Nov 7, 2009 #2


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