Why About Everything?

Why does present electricity runs on A.C rather than D.C?

Direct current flows only in one direction.Alternating current flows back and forth continuously. Thomas Edison was a proponent of direct current,which worked find in the early days of electric light, because the generators were very close to the lights that used electricity.

     But as demand for electric light increased, D.C. proved inadequate. Electric current loses the least energy when traveling at high voltages. It was then uneconomical to transform D.C in the high voltages necessary for long-distance transmissions. Direct current circuits would have required generating stations every three or four miles, unfeasible in the present scenario of sprawling cities.

http://www.diffen.com/difference/Alternating_Current_vs_Direct_Current

      In 1885, young man named George Westinghouse bought the U.S. patent for alternating current from inventor Nikola Tesla. Not only could A.C. transmit higher voltages more cheaply than D.C., the voltages could be raised or lowered by switching only one transformer. With its relative flexibility and lower cost, A.C quickly became a widely accepted standard.