## Electric Current

##### What is an electric current?

An electric current is a flow of charge. In a metal or a wire, the electric current charge is carried by conduction of electrons which are not attached to any given fixed ion of the metal.

##### What is the unit of electric current?

The unit of electric current is the ampere. The definition of the ampere is given below.

One ampere is the constant current that if maintained in tow parallel conductors of infinite length, of negligible circular cross section and placed 1 m apart in a vacuum, would product between those conductors a force of 2 x 10 -7 N per meter length.

##### What is a coulomb (C)?

A coulomb (C) of electric charge is the charge which passes a given point when 1 ampere of steady current flows for 1 second. Therefore, a steady current of 3 Ampere for 5 minutes means that a charge of 3 x 5 x 60 = 900 C has been passed in total. The link can be expressed in the formulas and equations below. t is time.

Charge Q

Current I