Light Bulb
From DT Online
Bulbs are used as a form of illumination or indication and the type commonly used has a filament coil which glows white hot when a current passes through it. The filament is in a space filled with an inert gas to aid light output and to prevent oxidisation of the filament
Bulbs consume more power than LEDs but give a high light output. There are two common types of bulb used in schools MES and LES - which are smaller in physical size than MES types. They may be bayonet or screw cap but screw types are more common.