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Incandescent Light Bulb

The incandescent light bulb provides a source of electric light through incandescence. The bulb works by passing current through a filament which heats to a temperature that produces light. The glass bulb that contains the filament prevents oxidation of the hot filament. The bulbs are also called electric lamps.

Incandescent bulbs come in a various sizes and voltages. They can range from 1.5 volts to 300, require no external regulating equipment and have low manufacturing costs. They work well on alternating or direct current. Due to this is it used commonly in residential, commercial, and portable lighting. The heat of the bulb is used in some instances such as incubators, brooding boxes for poultry, infrared heating for industrial heating and drying processes. In winter the bulbs help contribute heat to buildings but in summer bulbs increase the cost of air conditioning.

Incandescent bulbs are slowly being replaced by other types of light such as fluorescent, high-intensity discharge lamps, and light-emitting diodes. Many of these new sources provide more light and less heat. In the US federal law has mandated that by 2014 incandescent bulbs be replaced by more energy-efficient light bulbs. Brazil has already phased out incandescent bulbs.

Although Thomas Edison is considered the inventor of the incandescent lamp, historians Robert Friedel and Paul Israel list 22 inventors of the lamps prior to Edison. However, Edison’s version was better due to incandescent material, a higher vacuum than the others, and a high resistance that made power distribution from a centralized source economically viable.

Edison viewed the lamp as just a component in his electric system. Edison’s system is what set him apart from the other inventors. Humphry Davy, in 1802, produced the most powerful electrical battery in the world. He then created the first incandescent light by passing the current through a thin strip of platinum. It wasn’t bright enough or long lasting enough to be practical but it set a precedent for experiments the next 75 years. Davy also created the first arc lamp with two carbon charcoal rods connected to a 2000-cell battery.
James Bowman Lindsay demonstrated a light that stayed constant and allowed one to read at a distance of one and half feet. Lindsay moved on to the wireless telegraph soon after and didn’t develop the light any further. Warren de la Rue used a coiled platinum filament, which has a high melting point, allowing the filament to operate at high temperatures and for longer. The design was efficient but not cost effective due to the cost of platinum. Frederick de Moleyns received the first patent for an incandescent lamp, in 1841, when he used platinum wire within a vacuum bulb. John W. Starr acquired a patent for his incandescent light bulb which used a carbon filament in 1845. He died before he produce the bulb commercially.

In 1854, Heinrich Göbel filed a suit claiming he developed the first light bulb in 1854. He claimed five years he developed what many call the first practical light bulb. Lewis Latimer later discredited Göbel proving that the bulb he claimed to have created in the 1850′s was actually built much later. Joseph Wilson Swan was the first to have his home lit by light bulbs. Edison started his research for a practical lamp in 1878. Eventually his research returned him to the carbon filament. His first successful test lamp lasted 13.5 hours. Edison discovered that carbonized bamboo filament could last over 1200 hours.

The United States Electric Company, founded my Hiram S. Maxim, was the second company, after Edison’s, to sell practical incandescent electric lamps. Maxim coated his carbon filaments with hydrocarbons to extend their life. Later Maxim would develop a way to reduce breakage and create novel shapes out of the filaments. Edison and Swan’s companies merged to become Ediswan. Although this joint venture only happened after Swan sued Edison and forced him to merge. In 1881, the Savoy Theatre became the first public building to be lit entirely by electric lights. In 1882, the first Christmas lights on a tree was installed, however, this did not become popular for a while.
In 1883, the US Patent Office said Edison’s patents were based on the prior art of William Sawyer. In 1889, this ruling was overturned and Edison’s claim was validated. In 1902, Carl Auer von Welsbach produced the first commercial metal filament incandescent lamp. Willis Whitnew improved Welsbach’s design by creating a metal-coated carbon filament that wouldn’t blacken the inside of the bulb. In 1905, a tungsten filament lamp, which lasts longer than carbon, was produced by a Hungarian company called Tungsgram.

The cost of incandescent lamps has decreased by a factor of thirty since Edison’s lighting system was introduced. Consumption of incandescent bulbs has grew rapidly in the United States. In 1885 an estimated 300,000 general light service lamps were sold, all carbon filaments. In 1914 88.5 million lamps were used, in 1945 annual lamp sales were 795 million.

Incandescent Light Bulb


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