Editing Flashlight (section)

== Incandescent ==
[[File:Lightbulbs for flashlight.JPG|thumb|alt=Three miniature bulbs: tubular bulb with screw base, globular bulb with screw base, and prefocus bulb with flange-mount base|Miniature incandescent bulbs for use in flashlights: The tungsten filament bulb was essential to turn the flashlight from a novelty to a useful tool.]]

Incandescent flashlights use incandescent light bulbs, which consists of a glass bulb and a [[tungsten]] filament. The bulbs are under vacuum or filled with [[argon]], [[krypton]], or [[xenon]]. Some high-power incandescent flashlights use a [[halogen lamp]] where the bulb contains a [[halogen]] gas such as [[iodine]] or [[bromine]] to improve the life and efficacy of the bulb. In all but disposable or novelty flashlights, the bulb is user-replaceable; the bulb life may be only a few hours.<ref name=Kreith07/>

The light output of an incandescent lamp in a flashlight varies widely depending on the type of lamp. A miniature keychain lamp produces one or two lumens. A two-D-cell flashlight using a common prefocus-style miniature lamp produces on the order of 15 to 20 [[lumen (unit)|lumen]]s of light<ref>Cliff Gomer, ''High Beams'' in ''Popular Mechanics'', November 2003 pages 81-88</ref>  and a beam of about 200 [[candlepower]]. One [[Maglite|popular make]] of rechargeable focusing flashlight uses a halogen lamp and produces 218 lumens. By comparison, a 60-watt household incandescent lamp will produce about 900 lumens. The [[luminous efficacy]] or lumens produced per watt of input of flashlight bulbs varies over the approximate range of 8 to 22 lumens/watt, depending on the size of the bulb and the fill gas, with halogen-filled 12-volt lamps having the highest efficiency.{{citation needed|date=October 2012}}