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.