VOLTAGE

The basic unit of measure for potential difference is the volt (symbol V), and, because the volt unit is used, potential difference is called voltage. An object’s electrical charge is determined by the number of electrons that the object has gained or lost. Because such a large number of electrons move, a unit called the "coulomb" is used to indicate the charge. One coulomb is equal to 6.28 x 1018 (billion, billion) electrons. For example, if an object gains one coulomb of negative charge, it has gained 6,280,000,000,000,000,000 extra electrons.

A volt is defined as a difference of potential causing one coulomb of current to do one joule of work.

A volt is also defined as that amount of force required to force one ampere of current through one ohm of resistance.

The latter is the definition with which we will be most concerned in this module.

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