An uninterruptible power supply, commonly called a UPS is a device that has the ability to convert and control Direct Current (DC) energy to Alternating Current (AC) energy. It uses a conventional battery of 12V rating as the input source and by the action of the inverter circuitry, it produces an alternating voltage which is sent to the load. This particular UPS is designed for a small scale load like a personal computer and hence only a basic power rate is generated by the UPS. Standard Untinteruptible Power Supply (UPS) systems are connected in series between the AC mains and the critical load.