Page "Electricity" Paragraph 30

By historical convention, a positive current is defined as having the same direction of flow as any positive charge it contains, or to flow from the most positive part of a circuit to the most negative part.

Current defined in this manner is called conventional current.

The motion of negatively charged electrons around an electric circuit, one of the most familiar forms of current, is thus deemed positive in the opposite direction to that of the electrons.

However, depending on the conditions, an electric current can consist of a flow of charged particles in either direction, or even in both directions at once.

The positive-to-negative convention is widely used to simplify this situation.