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On this day, 120 years ago in 1892, Thomas Edison was granted a number of patents relating to electric lighting, including a “System of Electric Lighting”, an “Incandescent Electric Lamp”, a “System of Electrical Distribution” and an “Electric-Lighting System”. His initial design of the incandescent light bulb dates back even earlier, to 1879.

While inventions relating to the incandescent lamp had been suggested before Edison, his concept improved on previous attempts through the combination of three factors: a more effective and longer lasting filament, a higher vacuum than others were able to achieve, and a design that made power distribution from a centralized source economically viable.

Thomas Edison’s light bulb, lighting up our lives for more than a century.
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An incandescent bulb works by heating a filament to a high enough temperature that it starts glowing.  This is done by passing an electrical current through the filament.  To keep the filament from oxidizing and “burning out”, it is isolated in an enclosure (the glass bulb) that either contains an inert gas, or is evacuated to create a vacuum.

The invention of the incandescent light bulb fundamentally changed the world, providing convenient and affordable lighting to the masses.  While it has since been surpassed by newer and more efficient lighting technologies like compact fluorescent lights and light-emitting diodes (LEDs), it still holds a place of prominence and importance within modern society.