It was in 1882 that Edison provided electricity on a large scale for the first time. This, he provided to fifty-nine customers in Manhattan. Then in 1884, electrical training of Parsons gave the world the steam turbine. This steam turbine is now extensively used and about 80% of the world uses this turbine to generate electric power. Electrical courses provide information about all such scientists. Detailed studies are to be done of the major and minor theories which have application and which have significantly changed the outlook of the modern systems in an electrical course. AC current is preferred over DC current because it is safer, has better range and efficiency.