A lamp is a device that produces light from electricity. 灯 are commonly known as light bulbs, and are used to provide interior lighting for buildings and exterior lighting for evening and nighttime visibility. Smaller lamps are used to illuminate small spaces like cabinets, or even buttons and switches.
The most common lamp is the incandescent light bulb, which emits visible light when a wire filament is heated by an electric current. The filament is protected by a glass bulb that is filled with an inert gas, or a halogen mixture to extend filament life. 灯 are manufactured in a wide variety of sizes and shapes, with different light outputs and voltage ratings.
Other lamp types include a variety gas-discharge lamps, in which an ionized gas produces light when electric current is applied. Fluorescent lamps and germicidal lamps are gas-discharge lamps.