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Why does internal resistance occur?

  1. Nov 21, 2005 #1
    I know its because the electrons stop the current but thats about all i Know!!
    Any ideas
    also does internal resistance vary from rechargable and non rechargable batteries?

    thanks :D
  2. jcsd
  3. Nov 21, 2005 #2


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    Internal resistance is a model to account for the drop in voltage when large currents flow from an EMF element. This non-idealness of real voltage sources can be thought of in many ways. May be it is just the chemical process is unable to sustain constant voltage over a large current range. If it is an active EMF device, there is going to always be an output resistance which will become its internal resistance. Or you can imagine that inside a battery, there are circuits, metals, etc which can be a cause for some resistance. But as these 'resistors' are inside the battery so there is no way you can remove them.

    Different devices will have different internal resistances depending on their design.
  4. Nov 21, 2005 #3
    ok, also EMF is the amount of energy given per unit of charge (coulomb)
    what does it do to the electrons though?:shy:
  5. Nov 21, 2005 #4


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    EMF is the same thing as voltage, also known as electric potential. To better understand, let us compare it to the gravitational potential.

    The gravitational field works on masses. A mass falling through a gravitational field will lose gravitational potential. The electric field works on charges. A charge (electron) falling through a electric field will lose electric potential (voltage or EMF).
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