This research article demonstrates how to protect the power transformer from over load time. It is to controlling our desired voltage on various load times but the research gives some solution to avoid over voltage problem by automatic tapping technique. In this research tapping of transformer is selected automatically with the help of Peripheral Interface Controller (PIC) microcontroller. Effective use of potential transformer is to find out the precision in the system. The load voltage is measured by potential transformer which is given to precision rectifier. It will produce the accurate voltage levels. Here the things are using PIC microcontroller which is a flash type reprogrammable device in which system was already programmed. The Model was fabricated with Triode for Alternating Current (TRIAC) switches just as a switching devices and Peripheral Interface Controller microcontroller just as a control unit. In this research automatic control sections by using tap changer. In conventional methods industrialist used mechanical on load tap changer which is highly risk, because it does not produces constant output voltage and can create voltage dips. In this research it will be overcome above problem by using automatic electronic tap changer. It will produce constant voltage regulation and to measure variation of current.