Voltage stabilizers maintain a constant voltage supply. It is used to overcome the voltage fluctuations in the supply that we are getting. A stabilizer consists of a transformer, relays and a control circuit. When the supply voltage reduces below the normal value the control unit and relays operate to increase the secondary voltage of the transformer and maintains at the normal level and supplies to the equipment connected via stabilizer. When the supply voltage decreases than normal value, the control unit and relays are operated such that the voltage at secondary is increased and is maintained at the normal value which is given to the equipment connected to the stabilizer.