the ratio of the electric current flowing at a particular point in a conductor to the cross-sectional area of the conductor taken perpendicular to the current flow at that point. It is measured in amperes per square metre
Symbol: J
current density in American English
the amount of electric current passing through a cross-sectional area (perpendicular to the direction of current) of a conductor in a given unit of time: commonly expressed in amperes per square centimeter or amperes per square inch