When sudden power failure occurred UPS (Uninterruptible Power Supply) works as a power back up. These UPS are used to protect computers, data centers from loss of current works. When power failure happened it makes beep sound to notify the user and it gives back up power supply for 15 – 20 minutes (This depends on the UPS). During this time users can save their current tasks and shut down the computer properly. But if the computer needs to be work even in a power failure generator needs to use. Currently, the companies, offices, and shops are using both UPS and generators.