# 12 - Phys102 Lecture 12 Electric Currents and Resistance...

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Phys102 Lecture 12 Electric Currents and Resistance Key Points Ohm’s Law Resistivity Electric Power Alternating Current References SFU Ed: 25-1,2,3,4,5,6,7. 6 th Ed: 18-1,2,3,4,5,6,7

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Volta discovered that electricity could be created if dissimilar metals were connected by a conductive solution called an electrolyte. This is a simple electric cell. 25-1 The Electric Battery
A battery transforms chemical energy into electrical energy. Chemical reactions within the cell create a potential difference between the terminals by slowly dissolving them. This potential difference can be maintained even if a current is kept flowing, until one or the other terminal is completely dissolved. 25-1 The Electric Battery

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Electric current is the rate of flow of charge through a conductor: Unit of electric current: the ampere, A: 1 A = 1 C/s . 25-2 Electric Current The instantaneous current is given by:
A complete circuit is one where current can flow all the way around. Note that the schematic drawing doesn’t look much like the physical circuit! 25-2 Electric Current

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By convention, current is defined as flowing from + to -. Electrons actually flow in the opposite direction, but not all currents consist of electrons.
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