Thursday, January 8, 2015


 Invention of Light Bulb illuminated our dark nights and made human existence hospitable for different human activities. It was a kind of revolution in human existence. There is also a story behind this revolutionary invention. Let us throw a light on the invention of light bulb.

 In 1806,  Humphrey Davy, an Englishman, demonstrated a powerful electric lamp illumination by creating a blinding electric spark between two charcoal rods, known as an "arc lamp,". This lamp required  tremendous source of power and the batteries so was impractical for most uses.

Now Scientists knew that if some material got hot enough, it will start glowing. This method could be employed for producing light. The problem with this method of making light was that material would burst into flame or melt into a puddle. If incandescent light was to be made practical, these twin problems would have to be solved.

In 1820, Warner Rue produced light bulb by passing electric current through platinum coil in empty tube. But because platinum was very expensive, this bulb was not really commercially feasible. In 1840, Joseph Swan invented a light bulb using carbonized, paper filament. He also patented the bulb in year 1860. But the bulb used to show dim light and was not at all long lasting.
It was found that to keep incandescent "burners" from catching fire was to not let them come into contact with oxygen. Oxygen is a necessary ingredient in the combustion process. Since oxygen is in the atmosphere, the only way to keep it away from burning was to enclose the burner in a glass container, or "bulb," can be saved from burning by pump out the entire air.

In 1841 a British inventor named Frederick DeMoleyns patented a bulb using just this technique in burners made of platinum and carbon. An American named J. W. Starr also received a patent in 1845 for a bulb using vacuum in conjunction with a carbon burner. 

Many others, including an English chemist named Joseph Swan, improved and patented versions of bulbs using a vacuum with burners of various materials and shapes. None, however, proved practical for everyday use. Swan's lamp, for example, used carbonized paper that would quickly crumble after being lit a short time.

Sir Thomas Eliot made the bulb commercially feasible in the year 1875. He had tirelessly worked towards making light bulb better. He also introduced a bamboo filament lamp soon after working on light bulb. By using Herman Spiegel’s vacuum pump, he successfully created vacuum inside his lamp’s chamber.

Thomas Edison did not really invented light bulb but had worked on it to offer an improved version. In 1879, with the help of low current electricity, improved vacuum, carbonized filament, he produced long lasting ad reliable source of light. He tried to offer practical lighting for homes. After working for around 18 months, Edison attained success in form of incandescent lamp that had filament of the carbonized thread that burned for around fourteen hours.

Electric light’s success brought name to Thomas Edison. He achieved great heights of wealth and fame as the electricity had spread throughout. His different companies continued to expand until 1889 and then Edison General Electric came into being. Even though company was in his name, he did not control it. Need for capital for developing lighting industry persuaded him to involve bankers like J.P Morgan. In year 1892, he merged the company with leading opponent Thompson-Houston and company’s name became General Electric.

Edison soon realized that any good burner would have to have a high electrical resistance, otherwise too much electricity would be needed to warm the material to the point where it would give off light. All materials have an amount of electrical "friction" that resists electricity moving through it. This is known as the material's electrical resistance. Materials with high resistance more easily get hot when electricity passes through them.

More carbonized organic materials were tested and Japanese bamboo proved to be the best. By the end of 1880 Edison's carbonized bamboo burners, now called filaments because they were fashioned into a long, thin thread, were burning in bulbs as long as 600 hours. The "filament" proved to be the best shape to increase the materials electrical resistance and physical strength.

The carbonized bamboo had a high resistance and fit well into Edison's scheme for building a whole electrical power system to provide lighting. By 1882 he had established the Edison Electrical Light Company which had a generating station located on Perl Street, providing New York City with electrical lighting. In 1883 Macy's in New York City became the first store to install the new incandescent lamps.

In 1901, Peter Hewitt introduced mercury vapor lamp that emitted bluish white lighting. Later on, brighter lamp using sodium vapor was invented. Willies Whitney came up with metal covering or carbon filament to prevent it from burning and charring, in turn making the bulb black. In 1906, General Electric launched tungsten filament that had higher melting point.

 Though Thomas Eliot knew the use of the metal but he did have machinery for developing it during his time. In the year 1910, another engineer named William Coolidge invented tungsten filament that lasted longer. Beginning of 1920 witnessed discovery of frosted light bulb and its use in neon lights and cars. In the year 1930, photographic flash bulb was discovered. And with 1940s entered soft incandescent bulbs, with 1950s came quartz glass for halogen bulbs. 1960s and 70s made way for the ellipsoid reflector, metal halide lamp. And finally in year 1990, Philips launched 60,000-hour bulb using magnetic induction.

 Now bulbs have come a long way and scientists are working 24x7 to offer power saving, efficient and environment savvy bulbs. CFLS and LED bulbs are replacing the incandescent bulbs. Though a little costlier, they are environment friendly and power saving. Incandescent bulbs can be reasonably characterized just as heater that produces lights. As the typical incandescent offers only 3-5% light of the total energy it takes up. Remaining energy is wasted as heat. CFLs on the other side employ 75% lesser energy in the comparison and lasts 10 times longer. Useful long life and efficiency adds to the popularity of CFLs.

 LED is more energy efficient than CFLs too. Standard LED offers around 35 lumens of light per watt as compared to around 12 lumen offered by an incandescent bulb. LED bulbs are getting developed and soon they would offer 131 lumens every watt. These are used in trail lights of trucks and cars, watch dials, digital clocks, traffic signals, Christmas lights. Long life and durability has made it popular these days. It has become an ideal lighting for homes. One can find a range of LED bulbs in the market.

 From simple light bulbs to CFLs and LEDs, bulbs have covered a long way. Hardly did we know that small thing like bulb can literally illuminate our lives.  

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