In earlier days, before the invention of fire, people had to stay all night in darkness inside a cave. They couldn’t do any of their work at night. But now, we can’t live without light. We have bulbs which glow and spread light through electricity. Invention of these bulbs changed the human lifestyle entirely. It may become hard to differentiate between day and night for the people who stay at home all day. Electric bulb is one of the greatest inventions of all time.
History of electric bulbs:
Thomas Edison is not the first one to invent electric bulb. Some others are,
In 1802, Humphry Davy invented the first light which works on electricity. After Alessandro Volta invented a continuous source of electricity, Humphry Davy experimented on that. After so many attempts, he created a battery which stores charge particles. Then he connected this battery to a piece of carbon wires. carbon glowed brightly with help of electricity. but the brightness was too much to use commercially.
Warren de la Rue
After Humphry, many scientists created light bulbs, but they failed due to lack of practical application. The most known invention among them is by Warren de la Rue. He enclosed a platinum coil inside a vacuum tube and passed electricity. His idea was based on the high melting point of platinum and it would take too much temperature to melt and vacuum will make it more durable. Although it was a great invention, the high cost of platinum would have become much costlier for the commercial use.
Joseph Wilson Swan
In 1850, Joseph Wilson Swan created a light bulb by placing filament of carbonized paper inside a vacuum glass bulb. In 1860 he introduced a working prototype of it. But it failed due to the lack of a good vacuum tube at that time. After some times, he continued his work and created a long lasting bulb using cotton thread. He also solved the problem of early blackening of the bulb.
Henry Woodward and Mathew Evans
After this, on July 24, 1874, Canadian patent was made by Henry Woodward and Mathew Evans. They created a number of bulbs with different shapes and sizes of carbon rods held between electrodes placed in nitrogen. And they tried to commercialize their work, but they didn’t succeed. They sold their patent to Edison in 1879.
In 1878, Thomas Edison did serious research on development of incandescent lamps and he became successful in that and filed a patent for Improvement In Electric Bulb. After that, he continued his experiment on finding the best material for metal filament. On November 4, 1879, he filed another US patent for an electric lamp using “a carbon filament or strip coiled connected to platina contact wires”.
Although the patent described many ways of creating carbon filament, after sometime the patent was issued, Edison and his team discovered that carbonized bamboo filament could last over 1200 hours. After this discovery, in 1880, Edison’s company, ‘Edison Electric Light Company’ started marketing its new product, the incandescent bulb.
Types of electric bulb
It makes the room warmer when it emits light. It consists of a tungsten filament, which glows with passed electricity. The filament is kept in a glass bulb containing vacuum or nitrogen gas. It is available in different sizes and shapes. But,there is chance of burning out of filament. It usually lasts for 700 to 1000 hours and it consumes more electricity.
This bulb is better and complex than the incandescent bulb. It contains mercury and other gases in a glass tube. When electricity is passed to the cathode, the gases will absorb the energy and excite mercury vapors along with other gas and emit radiant energy. This radiant energy is converted to light by phosphorous coating outside. The luminous effectiveness of this bulb is 50 to 100 lumens per watt, which is much greater than incandescent. The price of this bulb is costly, since it uses electric ballast to limit the flow of electricity. But it consumes less electricity compared to incandescent and emits the same amount of light.
3.Compact fluorescent Bulbs
It is made of approximately the same size as that of fluorescent, but with more efficiency. This has a longer lifespan of 10000 hours. This is designed as multiple tubular loops, containing mercury gas in it. The light will be emitted when electricity is passed through it. The problem with using mercury is that it would be hard to dispose it.
This is similar to incandescent, but it’s a better version. In place of tungsten filaments, it consists of a transparent envelop. The bulb is filled with halogen along with inert gases. When the electricity is passed it will glow. The inert gases used in it will increase the lifespan and luminosity of the light.
5.Light Emitting Diode
LED is the most developed version of electric bulbs. It is more efficient and brighter with less power consumption. The principle of light emitting in LED is Electroluminescence. It uses a semiconductor diode, which emits light when electricity is passed. When electricity is applied to a negatively charged diode, the electrons move and release photons, which collectively emits light from the diode. NOW, LED with different colours are available in market.
Importance of electric bulb
It allowed us to extend the work hours, before electric bulbs people had to work in candle light, which cannot be used in various places like forest, industries with fuel engines, where it might cause fire hazard and other serious problems. But now, we can work without fear for those hazards and we can work all night, if necessary.
UV light with wavelength around 200 to 300nm can kill germs. Hence it is used in hospitals, as germ removing techniques. During corona times, many hospitals used UV light based disinfection trolleys to disinfect hospitals rapidly and efficiently.
Nowadays a function without colourful lighting would look so dull. The colour lighting in weddings and other functions make people active and they enjoy the function.
It also plays a major role in vehicles, for night rides. Without light there would not be any transportation facility at night. In case of medical emergencies, if the patient has to wait till the dawn of night, he might die waiting. It is also useful in traffic lights.