AC power vs. DC power: Both are necessary in our everyday lives and switching between the two causes a great deal of strife in electronics. Why do we need both?
As some of you may or may not know, there was a long standing battle between the two types of power raging back in the 1880s between two giants. The proponents of this war knew that whoever won would determine the future of the power distribution in the United States and possibly the world. In the first corner was Thomas Edison and his company that would eventually become General Electric; Edison wanted the world to run on DC. In the other corner was Westinghouse Corporation, funded by George Westinghouse and led (intellectually) by Nikola Tesla. Westinghouse represented AC power and would be the eventual winner. You can read more about the battle HERE, but I thought it would be interesting to point out that this battle eventually became a political one. Edison even started fighting dirty, secretly funding the invention and use of the first electric chair powered by AC, in order to give some bad press.
AC of course won out over DC as the power distribution of choice, mainly because of the ability to have large generators in a central location and then transmit the power efficiently over power lines to homes and businesses. DC would have required local generators on every street or even every home, which was not possible nor economically viable at the time.