Halogen lamp

<p>A halogen lamp (also called tungsten halogen, quartz-halogen, and quartz iodine lamp) is an <a href="/facts/Incandescent_light_bulb/31frjg0A">incandescent lamp</a> consisting of a <a href="/facts/Tungsten_filament/31frjg0A">tungsten filament</a> sealed in a compact transparent envelope that is filled with a mixture of an <a href="/facts/Inert_gas/3EkBEoYh">inert gas</a> and a small amount of a <a href="/facts/Halogen/YeFgWHeA">halogen</a>, such as <a href="/facts/Iodine/JlfMecMf">iodine</a> or <a href="/facts/Bromine/oLfj3C7D">bromine</a>. The combination of the halogen gas and the <a href="/facts/Tungsten/WYwbNDYX">tungsten</a> filament produces a halogen-cycle chemical reaction, which redeposits evaporated tungsten on the filament, increasing its life and maintaining the clarity of the envelope. This allows the filament to operate at a higher temperature than a standard incandescent lamp of similar power and operating life; this also produces light with higher <a href="/facts/Luminous_efficacy/ryvu6nvc">luminous efficacy</a> and <a href="/facts/Color_temperature/g77MjsPM">color temperature</a>. The small size of halogen lamps permits their use in compact optical systems for <a href="/facts/Projector/ucQKkpAS">projectors</a> and illumination. The small glass envelope may be enclosed in a much larger outer glass bulb, which has a lower temperature, protects the inner bulb from contamination, and makes the bulb mechanically more similar to a conventional lamp.
</p><p>Standard and halogen incandescent bulbs are much less efficient than <a href="/facts/LED_lamp/kMsxpkk9">LED</a> and <a href="/facts/Compact_fluorescent_lamp/gRsYSlYD">compact fluorescent lamps</a>, and therefore have been or are being <a href="/facts/Phase-out_of_incandescent_light_bulbs/MBrswyk5">phased out in many places</a>.
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Halogen lamp open-in-new

Halogen lamp