Thomas Alva Edison, U.S. inventor, best known for his development of the phonograph and the incandescent lamp, was even more notable for the wide range of his interests.

He was born in Milan, Ohio, on February 11, 1847. He was experimenting for some time with what he called "electric lamp for giving light by incandescence." On October 21, 1879, in his laboratory in Menlo Park, New Jersey, after spending more than $ 40000 in fruitless experiments, he finally succeeded in making an incandescent lamp in which a loop of carbonized cotton thread glowed in a vacuum glass bulb for more than 40 hours. He himself described the event as "the sight we had so long desired to see met our eyes." The following decade was devoted to the invention and exploitation and methods for the generation and distribution of electricity, including the three-wire system.

In his life time of 84 years (he died in 1931), he patented over 1000 inventions which changed our way of living. In 1883 he patented what became known as the "Edison  effect",  the  passage  of  electricity from a filament to a plate of metal inside an incandescent lamp globe (a forerunner of  the electron  tube).

His invention of the electric bulb, in a way,  revolutionalized   the   technical   and social development of mankind. This small ubiquitous device which is so familiar today, is really a gift to the humanity by this great scientist, who worked hard to continuously improve its performance ever since its invention.

In the course  of years,  the method  of production of electric bulb has developed from manual techniques to a completely mechanical activity in order to  cater  to the ever increasing demand all over the world, and, as a result of it, a new great break-through was achieved in incandescent lamp technology with the halogen lamp having a luminous efficacy of 20 to 30 lumens per watt.

In an indirect way, the incandescent lamp has  been  the  motive  power  behind  all further development in the industrial and domestic use of electricity. The fact that radio valves were derived originally from the incandescent lamp, confirms the origin of electronics and  its  later  development as well. The electric lamp, without doubt, has brought 'Light for everybody' and is still doing so!

The Posts  and Telegraphs  Department feels privileged in honouring Thomas Alva Edison by issuing a  special postage stamp commemorating the invention of electric light bulb by him one hundred years ago.

Source : Information Folder issued by Indian Posts & Telegraph Department, Government of India