Museo Galileo
italiano
Virtual Museum
In-depth
Electric current
Electric current

An electric current is produced by the flow of charges. This motion can occur not only in a solid conductor (copper wire), but also in a liquid or gas. If the movement is unidirectional—i.e., in only one direction, like water in domestic pipes—the resulting current is continuous. If, instead, the direction of flow changes periodically, an alternating current is obtained.