The Incandescent lamp also known as electric lamp or Filament lamp, but better known as the Electric Bulb is a source of electric light that works by incandescence. An electric current passes through a thin filament, heating it to white hot until it produces light. The enclosing glass bulb prevents the oxygen in air from reaching the hot filament, which otherwise would be destroyed rapidly by oxidation. Incandescent light bulbs come in a range of shapes and sizes. 







ADVANTAGES -

·  Availability: Incandescent bulbs are easily available in a wide range of sizes and voltages, from 1.5 volts to about 300 volts.

·  Extra equipment: They require no external regulating equipment and work well on either alternating current or direct current.

· Colour Rendering: They produce warm light colour and have excellent colour rendering (Ra-!00) which means, the colours of objects under this light appear almost the same as in daylight.

· Disposability: They are easily disposable as they do not contain any hazardous material to the environment.
USAGE:
For these reasons, the incandescent lamp is widely used in household and commercial lighting, for portable lighting, such as table lamps, some car headlamps and electric flashlights, and for decorative and advertising lighting.





DISADVANTAGES -

·  Luminous Efficacy: The Incandescent Bulbs have poor luminous efficacy - for every watt of energy consumed, only 12 to 14 lumens of visible light is produced. This is because approximately 90% of the power consumed by an incandescent light bulb is emitted as heat, rather than as visible light.

·  Life: They have a short life - just about 1000 hours, in comparison to other lamp types.
Because of their disadvantages, some jurisdictions are even attempting to ban the use of incandescent light bulb in favour of more energy-efficient lighting like CFL- Compact Fluorescent lamps and other gas-discharge devices, which give more visible light for the same amount of electrical energy input.