DIVISION OF CURRENT

                                     PRIMARY CELL

It essentially consists of two dissimilar conducting electrodes immersed in a liquid called electrolyte which acts chemically on one of the two electrodes more readily than on the other. By using the energy released by chemical action, electrons are shifted from one electrode to another thereby creating a potential difference between the two electrodes. The value of total potential difference created between the electrodes, when the cell is not connected to an external circuit, is known as its electromotive force.

Now, every cell has some internal resistance which depends upon the construction and condition of the cell. The internal resistance depends on the area of electrodes, the distance between the electrodes, the temperature, strength and density of the electrolyte. When the cell supplies current to an external circuit, there is always some internal voltage drop due to this internal resistance. Hence, the voltage available for external circuit is decreased by this amount. The net voltage available at the terminals for external circuit is known as the terminal potential difference.