“…The invention of the first, practical, incandescent lamp occurred in 1878 and is ascribed to Swan, working in England and Thomas Alva Edison working independently, in the United States. The latter was granted a U.S. Patent in 1880. The resistance of a thin wire filament to a flow of electric current causes it to heat up, almost instantly, to a temperature at which it is incandescent. The filament would quickly burn out in the presence of oxygen, however and accordingly, it is enclosed within a glass envelope, which is evacuated and refilled with an inert gas, usually argon or nitrogen and occasionally krypton. Various materials were considered for filaments, including bamboo and human hair but tungsten proved the most suitable, having a very high melting point…"

To read more interesting historical facts open the “A Little History” PDF.

View Product PDF's