A lamp is a replaceable component such as an incandescent light bulb

Incandescent light bulb

The incandescent light bulb, incandescent lamp or incandescent light globe makes light by heating a metal filament wire to a high temperature until it glows. The hot filament is protected from air by a glass bulb that is filled with inert gas or evacuated. In a halogen lamp, a chemical process...

, which is designed to produce light

Light

Light or visible light is electromagnetic radiation that is visible to the human eye, and is responsible for the sense of sight. Visible light has wavelength in a range from about 380 nanometres to about 740 nm, with a frequency range of about 405 THz to 790 THz...

 from electricity

Electricity

Electricity is a general term encompassing a variety of phenomena resulting from the presence and flow of electric charge. These include many easily recognizable phenomena, such as lightning, static electricity, and the flow of electrical current in an electrical wire...

. These components usually have a base of ceramic, metal, glass or plastic, which makes an electrical connection in the socket of a light fixture

Light fixture

A light fixture, light fitting, or luminaire is an electrical device used to create artificial light and/or illumination, by use of an electric lamp...

. This connection may be made with a screw-thread base, two metal pins, two metal caps or a bayonet cap. Re-lamping is the replacement of only the removable lamp in a light fixture.

Lamp circuit symbols

In circuit diagram

Circuit diagram

A circuit diagram is a simplified conventional graphical representation of an electrical circuit...

s lamps usually are shown as symbols. There are two main types of symbols, these are: