We are familiar with air current and water current We know that flowing water constitute water current in rivers. Similarly if the electric charge flows through a conductor (for example though a metallic wire) we say that there is a electric current in the conductor. In a torch we know that the cells (or a battery, when placed in proper order) provide flow of charge or an electric current through the torch bulb to glow. We have also seen that the torch give light only when its switch is on. What does a switch do? A switch makes a conducting link between the cell and the bulb. A continuous and closed path of an electric currrent is called an electric circuit. Now if the circuit is broken anywhere the current stops flowing and the bulb does not glow. how do we express electric current Electric current is expressed by the amount of charge glowing through a particular area in unit time. In other words, it is the rate of flow of electric charges. In circuits using other words, it is the rate if flow of electric charges. In circuits using metallic wires, electrons constitute the flow of charges. However, electrons were not known at the time when the phenomenon of electricity was first observed so, electric current was considered to be the flow of positive charges and the direction of flow of positive charges was taken to be the direction of electric current. Conventionally, in an electric circuit the direction of electric current is taken as opposite to the direction of the flow of electrons, which are negative charges. If a net charge flows across any cross section of a conductor in time then the current through the cross section The SI unit of electric is coulomb which is equivalent to the charge contained in nearly electrons The electric electron possesses a negative charge of the electric current is expressed by a unit called ampere named after the French scientist Andre-marie