The incandescent light bulb or lamp is an electric light source that operates on incandescence, which is the emission of light created by heating the filament. They are available in a wide range of sizes, wattages, and voltages.
Incandescent bulbs were the first type of electric lighting and have been in use for over a century. While Thomas Edison is commonly regarded as the inventor of the incandescent light bulb, a number of people produced light bulb components and prototypes long before Edison.
One of these individuals was British physicist Joseph Wilson Swan, who got the first patent in 1879 for a complete incandescent light bulb with a carbon filament. Swan’s residence was the world’s first to be lit by a light bulb. Edison and Swan joined their enterprises, and they were the first to design a commercially viable light bulb.
An incandescent bulb is typically made out of a glass shell that houses a tungsten filament. An electric current flows through the filament, heating it to a temperature high enough to create light.
Incandescent light bulbs typically have a stem or glass mount affixed to the bulb’s base, allowing the electrical connections to pass through the envelope without leaking gas or air. The filament and/or its lead wires are supported by small wires inserted in the stem.
To retain and protect the filament from evaporation, the enclosing glass enclosure contains either a vacuum or an inert gas.