Invention and Working of Electric Bulb

We all are a part of an electrified world. Light bulb, particularly, profoundly revolutionized human existence. It not just helped in illuminating nights but also made human existence hospitable for an array of human activities. History of electric light, which adds to our daily convenience, bears testimony of many scientists, physicist’s efforts. Some people who took a step forward in the field were James Lindsay, Frederick Moleyns, Heinrich Göbel, Humphrey Davy and Warren Rue and Thomas Edison.

Humphrey Davy offered a miner lamp by working out on formulation for electric arc. In year 1802, he demonstrated workings of electric arc with the help of 2 wires- one attached to battery and other to the thin charcoal piece. In 1820, Warner Rue produced light bulb by using platinum coil in empty tube and passing electric current through it. But this bulb was not really commercially feasible due to costly platinum used.

Hence various scientists started the search for finding suitable filament for bulb. Soon James Joule advocated that the electric current when passed via conductor with the high resistance produces thermal energy, generating light energy. But quest for finding right filament which was practical, inexpensive, commercially feasible was still on. In 1840, Joseph Swan established earliest functional light bulb with the help of carbonized, paper filament. He also patented the bulb in year 1860. But the bulb produced dim light and was not at all long lasting. It needed a power source nearby to function all the time.

With similar technology, 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.

Another known name that contributed to development of electric, incandescent light is Thomas Edison. He 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. Eventually he not only gave us incandescent lighting but also gave electrical lighting mechanism containing necessary elements to make incandescent light safe, economical and practical. 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.

While using most of energies on what kind of filament would work for bulb; Edison was inventing seven systemic elements critical for practical use of electric lights. These lights were an alternative to gas lights that were used then. He publically demonstrated his incandescent lighting mechanism in December 1879 and then spent several following years in development of electric industry.

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.

Originally, shape of glass bulb was designed by Matthew Evans and Henry Woodward. During this period, scientists had been working on new figure of electric arc, discharge lamps, first with help of carbon dioxide within bulb and then by using noble gases krypton and argon. They did this to add to the bulb’s efficiency.

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 also used by a lot of people and 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. LEDs are used at a lot of places. 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. 

Parts of Electric Bulb

1. Outline of Glass bulb
2. Low pressure inert gas (argon, nitrogen, krypton, xenon)
3. Tungsten filament
4. Contact wire (goes out of stem)
5. Contact wire (goes into stem)
6. Support wires (one end embedded in stem; conduct no current)
7. Stem (glass mount)
8. Contact wire (goes out of stem)
9. Cap (sleeve)
10. Insulation (vitrite)
11. Electrical contact