In the kit Over/Under Voltage Protection many times there is a situation that the voltage level increases over the particular threshold limit in a circuit due to certain problems this situation is termed as over voltage .In this case the appliance can be damaged due to part being destroyed. In the kit Over/Under Voltage Protection first block is power supply in which the input is 230V AC which is step down using the transformer (12-0-12) .The 12V ac input is fed to the bridge diode to gives 12V pulsating DC. This DC voltage is filtered through the capacitor to remove the ripples. The filtered DC is fed to 7805 regulator to fetch +5v regulated output.
The Objective of the kit Over/Under Voltage Protection is to design a system to protect the system from the over voltage and under voltage condition. As the voltage increases the supply is cut off. In this there is also provision for under voltage protection.