Merge: date=March 2008 For: Light fixture

Incandescent light bulb

main: Incandescent light bulb Incandescent light bulb as we know it today, with a coiled filament of tungsten, was commercialised in the 1920s. It is sometimes confused with the carbon filament lamp introduced in about 1880. As well as bulbs for normal illumination, there is a very wide range, including low voltage, low-power types often used as components in equipment, but now largely displaced by LEDs

There is currently interest in banning some types of filament lamp in some countries, such as Australia planning to ban standard incandescent light bulbs by 2010, because they are inefficient at converting electricity to light. Less than 3% of the input energy is converted into usable light. Nearly all of the input energy ends up as heat that, in warm climates, must then be removed from the building by ventilation or air conditioning, often resulting in more energy consumption. In colder climates where heating and lighting is required during the cold and dark winter months, the heat byproduct has at least some value.

Halogen lamp

main: Halogen lamp

Halogen lamps are usually much smaller than standard incandescents, because for successful operation a bulb temperature over 200°C is generally necessary. For this reason, most have a bulb of fused silica (quartz), but sometimes aluminosilicate glass. This is often sealed inside an additional layer of glass. The outer glass is a safety precaution, reducing UV emission and because halogen bulbs can occasionally explode during operation. One reason is if the quartz bulb has oily residue from fingerprints. The risk of burns or fire is also greater with bare bulbs, leading to their prohibition in some places unless enclosed by the luminaire. Those designed for 12V or 24V operation have compact filaments, useful for good optical control, also they have higher efficacies (lumens per watt) and better lives than non halogen types. The light output remains almost constant throughout life.

Fluorescent lamp

main: Fluorescent lamp Fluorescent lamps have much higher efficacy than filament lamps. For the same amount of light generated, they typically use around ¼ to ⅓ the power of an incandescent.

Fluorescents were mostly limited to linear and a round 'Circline' lamp until the 1980s, with other shapes never gaining much popularity. The compact fluorescent lamp (CFL) was commercialised in the early 1980s.

Most CFLs have a built-in electrical ballast and fit into a standard screw or bayonet base. Some make use of a separate ballast so that the ballast and tube can be replaced separately.

Typical average lifetime ratings for linear fluorescent tubes are 10,000 and 20,000 hours, compared to 750 hours (110 V) and 1000 hours (240 V) for filament lamps.