Abstract: The main objective of this project is to provide uninterrupted power supply to a load, by switching automatically battery. The demand for electricity is increasing every day and frequent power cuts is causing many problems in various areas like industries, hospitals and houses. An alternative arrangement for power source is a must. In this project uses four switches to demonstrate the respective failure of that battery .When any of the auto switches is pressed it shows the absence of that particular source, switches are connected to system. The output of switches is given to the relay driver IC, which auto switches appropriate relay to maintain uninterrupted supply to the load. The output shall be observed using a LED drawing power supply from first battery initially. On failure of the first battery load is shift to another battery.

Keywords: Uninterrupted power supply (UPS),Liquid Crystal Display(LCD), Threshold voltage(Vth).