DC Circuits

Electromotive Force

Batteries, by their very nature, introduce resistance as well as a potential difference.

This script "E" is called the "electromotive force" or "emf"; it is the voltage of the battery when there is no load, so the current is zero.

When there is a load on the battery -- that is, when there is a current -- the voltage across the terminals of the battery is reduced by an amount I R_int -- the " I R - drop " due to the internal resistance of the battery.

Homework Assignment			Series Circuits
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