AC - technical definition

Current is the flow of electrons through a metallic circuit, with the direction of flow being from positive (+) pole to negative ( ) pole outside of the source (generator or battery). Direct current (DC) travels in one direction, only, while alternating current (AC) travels in both directions across the circuit. A continuous flow of AC current travels first in one direction and then reverses polarity and flows in the opposite direction. See also current, DC, and polarity.