The Electric Bulb
Introduction
More than 150 years ago, inventors began working on a bright idea that would have a dramatic impact on how we use energy in our homes and offices. This invention changed the way we design buildings, increased the length of the average workday and jumpstarted new businesses. It also led to new energy breakthroughs -- from power plants and electric transmission lines to home appliances and electric motors.
Like all great inventions, the light bulb can’t be credited to one inventor. It was a series of small improvements on the ideas of previous inventors that have led to the light bulbs we use in our homes today.
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- Aim
A light bulb produces light from electricity. In addition to lighting a dark space, they can be used to show an electronic device is on, to direct traffic, for heat, and for many other purposes. Billions are in use, some even in outer space.
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- Problem
The problem with incandescents is you end up paying more in electricity costs. Incandescents are inefficient – 90% of the energy goes toward heat and only 10% toward light. Incandescents also don't last as long as CFLs and LEDs.
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- Need of invention
Where Edison succeeded and surpassed his competition was in developing a practical and inexpensive light bulb, according to the DOE. Edison and his team of researchers in Edison's laboratory in Menlo Park, N.J., tested more than 3,000 designs for bulbs between 1878 and 1880. In November 1879, Edison filed a patent for an electric lamp with a carbon filament. The patent listed several materials that might be used for the filament, including cotton, linen and wood. Edison spent the next year finding the perfect filament for his new bulb, testing more than 6,000 plants to determine which material would burn the longest.
Several months after the 1879 patent was granted, Edison and his team discovered that a carbonized bamboo filament could burn for more than 1,200 hours. Bamboo was used for the filaments in Edison's bulbs until it began to be replaced by longer-lasting materials in the 1880s and early 1900s.
In 1882, Lewis Howard Latimer, one of Edison's researchers, patented a more efficient way of manufacturing carbon filaments. And in 1903, Willis R. Whitney invented a treatment for these filaments that allowed them to burn bright without darkening the insides of their glass bulbs.
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- Principle
An incandescent bulb works on the principle of incandescence, a general term meaning light produced by heat. In an incandescent type of bulb, an electric current is passed through a thin metal filament, heating the filament until it glows and produces light.
Incandescent bulbs typically use a tungsten filament because of tungsten’s high melting point. A tungsten filament inside a light bulb can reach temperatures as high as 4,500 degrees Fahrenheit. A glass enclosure, the glass “bulb”, prevents oxygen in the air from reaching the hot filament. Without this glass covering and the vacuum it helps create, the filament would overheat and oxidize in a matter or moments.
After the electricity has made its way through the tungsten filament, it goes down another wire and out of the bulb via the metal portion at the side of the socket. It goes into the lamp or fixture and out a neutral wire.
This is an elegantly simple system and it works quite well at producing light. It’s perfect for a wide range of applications, cheap and easy to manufacture, and is compatible with either AC or DC current.
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- Diagram
- Cost
- CONCLUSION
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