Uninterruptible Power Supply (UPS) is a device consisting of solid state components that are connected between the input power source and the load, and prevents electrical disturbance of the power supply (mains electricity), such as a full power cut. Totally the UPS is available in three models, including Line Interactive,On-Line and Off-line. Regardless of the specific design of each UPS, several important features are in common. All kind of UPSs have got batteries and while mains electricity is available, it saves the energy in the batteries. As mains electricity cuts, energy of the battery converts into an alternating current (AC).Therefore, all systems must have a battery charger and inverter circuit. Also all UPSs have got a Bypass system with a switch on the output that provide a communication device with load for direct supply.Mostly, the output switch circuit is completed with the static switches. Also, in the low-power UPS, it is done by the relay. Borna niroo karan (Bornika) company is the agent UNIKA company in the fields of consultation, sales and distribution of power industry products including UPS is active.