Direct & Alternating Currents Gr 9 Science

Direct Current (DC) The current from a cell is called direct current because charged particles travel through a circuit in only one direction. In a cell, the electrons move from the negative to the positive terminal. Electronic devices such as MP3 players and cellphones use rechargeable batteries to supply DC current.

Alternating Current (AC) In an AC, the electrons move back and forth in the circuit, but there is no net movement of electrons in either direction. The electrical wires in our homes are part of a circuit that includes generation of electricity in a power station, to a transformer (an electrical device that changes the potential difference of an AC), transmission across the province, to substations and distribution to individual homes.

AC is used in homes and buildings because it can be transmitted at high potential difference over long distances, with only a small loss of electrical energy.