UPS are available in a variety of range in terms of design, features and capacity. Of all the available ones, a standby UPS is the most common one in use. It is used for domestic as well as office purposes. It works as a mediator between the main source of current and the computer. The main current supply flows through the UPS and conserves a part of it in its inverter battery cells that act as a secondary source of power for the computer during the power cuts. These are also referred to as offline UPS.