The Lightbulb http://inventors.about.com/library/inventors/bledison.htm A Lightbulb works by putting putting electric current through a filament the filament then heats up and glows causing light. The tricky part is finding a filament that doesn't burn out. To do that the filament is placed in a vacuum. Until 1879  such a filament hadn't been found, then Edison and his workers at Menlo Park refined the lighbulb. Thomas Edison is often credited with inventing the light bulb what he actually did was improve the light bulb. Edison improved the light bulb so much that he is considered to have invented it. He found a new filament and invented sockets with on off switch. Edison also made the lightbulb much more durable and made the vacum inside the bulb. He even made a new generator which was able to keep the voltage more constant than any other generator that had been made up until that point.

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