It is defined as the time rate of change of charge passing through a predetermined area with respect to time. It is caused by drift of free electrons through a conductor to a particular direction. The measuring unit of electric change is Coulomb and the unit of time is second, the measuring unit of electric current is Coulombs per second and this logical unit of current has a specific name Ampere after the famous French scientist André-Marie Ampere. Here the area is the cross-sectional area of the metal wire. If Δq units of charge flowing through the cross sectional area A in Δt units of time, then the resulting current i is given by,

\(i = \frac{\Delta q}{\Delta t}\) C/S

1 Ampere (A) = \(\frac{1\,\text{coulomb}}{\text{second}}=\frac{Q}{t}\)

The magnitude of electric current is measured in coulombs per second. The SI unit of electric current is Ampere and is denoted by the letter A. Ampere is defined as one coulomb of charge moving past a point in one second. If there are 6.241 x 10¹⁸ electrons flowing through our frame in one second then the electrical current flowing through it is ‘One Ampere.’