The INCANDESCENT lamp
Thomas Edison was the inventor of the first practical lamp in the world. Nevertheless, some other geniuses took part in this incredible and essential creation for the mankind. Get to know those who created this invention which is synonym of a good idea and is present in almost 100% of homes around the world!
Humphry Davy
Humphry Davy, in 1809, placed a thin carbon strip between two poles of a battery, creating a fleeting arc, which became the base that sustains the way in which a lamp works.
Warren de la RueIn 1840, Warren de la Rue placed a platinum filament inside an empty tube, where he passed electricity and burned it, emitting light and heat.
The almost absence of gas inside the tube, together with the high platinum resistance to heat, permitted that the filament material reached high temperatures without burning immediately. This was the first great durability lamp that we know of. The problem is that its high price made it commercially unfeasible. In the following years several variations of De la Rue’s model were tested, mainly in different filament materials and with a better vacuum of the glass capsule.
Henry Woodward and Matthew Evans
In 1874, Henry Woodward and Matthew Evans patented a lamp which basically was the same lamp invented by De la Rue and other inventors who were developing and improving after 35 years.
Joseph Swan
In 1850, Swan began to work in a lamp using carbonized paper filaments inside a vacuum glass bulb.
Thomas Edison
In 1879, Thomas Edison bought Woodward’ and Evans’ patent.
In that same year, Thomas Edison developed his own project of incandescent lamp. It was the first commercially feasible electric lamp.
His lamp was composed by a high resistance carbon filament in a high vacuum contained in a glass bulb.
How does the incandescent lamp work?
In the beginning the biggest challenge was to develop a resistant filament. Presently, the filaments are, generally, made of tungsten and metal, which only melt when submitted to a very high temperature.
In order to avoid that the filaments burn rapidly, the air of the lamp is totally removed, and it is filled with a mixture of inert gases, such as nitrogen, argon or krypton.
Process that happens when you connect a lamp to an eletric current:
1-When you turn a switch on, the electric current passes by the lamp through two drops of silver weld which a located on the bottom part;
2-They run along copper wires and are firmly fixed inside a glass column.
3-Between the two extremities of the copper wires there is another very thin wire, called filament, which is composed by tungsten.
4-When the current passes by this last wire it becomes incandescent, producing light and reaching up to 3000 degrees
Curiosities
Check some of the first patents in the lighting world
In 2008...
The incandescent lamp was prohibited to be commercialized in Europe. It was the European effort to save energy and to prevent the global warming. Until 2016 it will be prohibited in Brazil.
The Centennial Light Bulb
It is located in a fire squad in California (USA). It was installed in 1901 and is lit until the present day.
There are no studies to prove the veracity, but the durability enchants any person who finds this incredible “miracle”.
