Thomas Alva Edison holds 1093 patents on his inventions, which include such inventions as the incandescent light bulb, the phonograph, and direct current (DC). The latter being one of the most important and influential inventions since it was the first current to be invented. However, like any invention, it got its competition, this time, in the form of Nikola Tesla’s alternating current (AC). The war of currents between Thomas Edison’s direct DC and Nikola Tesla’s AC forever changed electricity and the way mankind lives. In order to be able to develop a successful incandescent lightbulb, Edison, had to first develop an entire electrical system, which he modeled after the gas lighting systems used in large cities. Gas systems had central stations, underground conductors, meters, and lamp fixtures. In addition to all of this, Edison also had to make an electrical generator and the network it powered. And so, Edison developed DC, which continuously runs in one direction. DC can be produced electrochemically by batteries and fuel cells or electromechanically by certain kinds of generators.
It can also be produced by photovoltaic devices. Edison designed a direct-current system that was most efficient for densely populated urban centers and for isolated plants providing power to a single building. His system was most efficient and economical within a square mile of the central station. Edison’s DC was initially the standard in the United States for electricity distribution as not only did DC work well with incandescent lamps, but DC systems could be directly used with storage batteries, providing valuable load-levelling and backup power during interruptions of generator operation. Also, Direct current generators could be easily paralleled, allowing economic operation by using smaller machines during periods of light load and improving reliability, and Edison had invented a meter to allow customers to be billed for energy proportional to consumption. This system however, had one simple flaw, which was that it couldn’t be easily converted to higher or lower voltages.
