If two charged bodies of different potential are placed one beside the other, the charges will not move from one body to the other. But if the two bodies are connected using a conductor, the flow of charges takes place. Charges will flow as long as there is potential difference between the two bodies. This rate of flow of electric charge is called 'electric current'.
Flow of Charges
A conductor having excess of electrons is said to be negative or at a lower potential and that having less electrons is said to be positive or at a higher potential. Under ordinary conditions the free electrons in a conductor move randomly in such a way that the net flow of charge across any section of the conductor is zero. No current exists in a conductor, unless a potential difference is applied between the ends of the conductor. Conventionally, the electric current is said to flow from a higher potential to a lower potential while the electrons flow from a lower potential to a higher potential i.e., the electric current flows in a direction opposite to the flow of electrons
A simple way of maintaining potential difference between the two ends of a conductor is by connecting it to a battery or a dry cell. In a cell/battery the potential difference between its two electrodes is maintained by the chemical processes between its electrodes and the electrolyte. Therefore a cell is able to maintain the potential difference of a conductor.
