Two theories describe current flow. The conventional theory, commonly used for automotive systems, says current flows from (+) to (-) ... excess electrons flow from an area of high potential to one of low potential (-). The electron theory, commonly used for electronics, says current flows from (-) to (+) ... excess electrons cause an area of negative potential (-) and flow toward an area lacking electrons, an area of positive potential (+), to balance the charges.
While the direction of current flow makes a difference in the operation of some devices, such as diodes, the direction makes no difference to the three measurable units of electricity: voltage, current, and resistance.
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