Computers and other electronic equipments are driven by the power but power failure can damage these equipments. About power failure, blackout, the loss of power that can occur because of a blown face or damaged power line can make a big problem for electronic equipments. At that time, you need a source of power to shutdown your computer or any other equipment. Standby power supply is a way of saving your computer as well other electronic appliances from any damage in power failure. It is helpful to keep your computer as well as other electronic devices running for several minutes. Within these minutes, you can save your data and shut down the computer. Standby power supply provides power to the load from a battery during a power failure consists typically of an inverter, a battery and a low capacity battery charger. Many residences now have a standby power supply for use during an outage.