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Voltage in short circuit

  1. Feb 7, 2013 #1
    We know that U=IR (ohm's law)
    in a short circuit, R goes to 0, I goes to infinity so the voltage goes to 0*∞ which is undefined!
    Why voltage is 0?
  2. jcsd
  3. Feb 7, 2013 #2


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    Gold Member

    Because in a short circuit, the potential difference is zero...

    Remember that voltage is the the difference between the potentials of two points, and a short circuit is -by definition- the situation where the two points have exactly the same potential.
  4. Feb 7, 2013 #3


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    Gold Member

    Nothing goes to infinity in reality, just in idea circuits. In real circuits the current is limited and/or something burns up and the circuit opens.
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