The practical units of electriciy being used by electrical engineers all over the world are based on the Metre-Kilogram-Second (MKS) system. The SI or the international System of Units (System International d` Unites) is an extension and rationalization of the MKS system. SI units have been adopted by the International Organization for Standardization (ISO) and recommended by almost all the leading scientific agencies of the world. More than 90 countries of the world have decided to make the SI the only legally accepted system. Clearly, it will become the universal currency for science and commerce.