The main function of the Stabilizer is to stabilize the voltage & safeguard the electrical equipment's. Energy saving is an added advantage. Highly fluctuation in AC supply is a common phenomenon in whole country. The voltage requirement of different electrical appliances is vary to a great extent. The electronics equipment like spectrophotometers, PH-Meter, X-Ray plant, recorders are all affected by high main voltage, whereas the refrigerators, deep freezers, incubators and other compressors are affected by low main voltage. How ever in industries, which are running 24 hours, also affected by this fluctuation voltage. So to achieve constant voltage Servo Stabilizers are used.