Electric current

Electric current, flow of electric charges. Protons, part of every atom's nucleus, have a positive charge; electrons surrounding the nucleus have a negative charge. Substances that freely give up electrons, such as aluminum, copper, and silver, are good conductors, allowing electric current to flow freely. Poor conductors, such as lead and tin, are more resistant to electric current. Substances that do not conduct electricity, such as glass and rubber, are insulators. Direct current (DC), used to power automobiles, always flows in 1 direction, while alternating current (AC), used in homes and for many electronic devices, reverses direction periodically.

See also: Alternating current; Direct current.