Electric current is defined as the rate of change of total charge flowing in a given time. It is measured in Amperes (A), where 1 Ampere is the amount of current that flows when 1 Coulomb of charge passes by in 1 second. Current (I) equals the total charge (q) divided by the time (t) taken (I=q/t). For non-uniform flow of charges, the current is calculated as the change in charge (dq) that flows across a cross-section over an infinitesimal time interval (dt), or I=dq/dt.