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Flashlight

*** Shopping-Tip: Flashlight
Image:Flashlight_450x190.JPG thumb|Green flashlight :''"Flashlight" is the NATO designation for the Yakovlev Yak-25 Soviet military jet.'' A '''flashlight''' or '''torch''' is a hand-held portable electric searchlight spotlight. It is known as a ''flashlight'' mainly in the United States and Canada and as a ''torch'' in most Commonwealth of Nations Commonwealth countries.

General information
Image:Incandescent flashlight spectrum.gif thumb|left|300px|The spectrum of an incandescent bulb type flashlight. A typical flashlight consists of a small electric lightbulb with associated paraboloid parabolic reflector, powered by battery (electricity) electric batteries, and with an switch electric power switch. The components are mounted in a housing that contains the necessary electric circuit and provides ease of handling, a means of access to the batteries for replacement, and a clear covering over the lightbulb for its protection. Although a relatively simple device, its invention did not occur until the late 19th century because it depended upon the earlier invention of the electric battery and incandescent light bulb. The batteries in the first ones were of such short useful life that the common method of operating them was to flash them just long enough to discern the environs, and only as needed; hence the term "flash-light". It is, however, reminiscent of the far-earlier "bullseye" lantern.

LED flashlights
Image:SurefireU2JPG.jpg right|300px|thumb|Electronically regulated, variable output LED flashlight Recently, flashlights which use light-emitting diodes (LEDs) instead of conventional lightbulbs have become available. LEDs have existed for decades, mainly as low-power indicator lights. In 1999, Lumileds Corporation of San Jose, CA introduced the Luxeon LED, a high-power white-light emitter. For the first time this made possible LED flashlights with power and running time better than some incandescent lights. The first Luxeon LED flashlight was the Arc Flashlight Arc LS in 2001. LEDs can be significantly more efficient at lower power levels, hence use less battery energy than normal lightbulbs. Such flashlights have longer battery lifetimes, in some cases hundreds of hours. At higher power levels, the LED efficiency advantage diminishes. LEDs also survive sharp blows that often break conventional lightbulbs. LED flashlights are often electronically regulated to maintain constant light output as the batteries fade. By contrast a non-regulated flashlight becomes progressively dimmer, sometimes spending much of the total running time below 50 percent brightness level. A common misconception about LED-based flashlights is that they generate no heat. While lower-power LED flashlights generate little heat, more powerful LED lights do generate significant amounts of heat. However the heat removal mechanism is different for LED flashlights. An incandescent light radiates away a significant fraction of the bulb heat in the beam itself. You can feel the warm beam from a nearby powerful incandescent flashlight or spotlight. By contrast an LED flashlight radiates little heat in the beam, so the excess emitter heat must be removed by conduction and transferred to the flashlight body. For this reason higher-powered LED flashlights usually have metal bodies and can become warm during use.

Other flashlight designs
A headlamp is a flashlight worn on the head for hands-free operation. Powerful headlamps mounted on helmets have been used in mining for decades, but general-purpose ones with fabric straps are now also available. Sometimes a light is mounted to a handgun or rifle [http://www.handgunsmag.com/tactics_training/lights_072804/] [http://www.policeone.com/writers/columnists/JohnMeyer/articles/98209/]. See also Streamlight. Most flashlights are cylindrical in design, with the lamp assembly attached to one end. However, early designs came in a variety of shapes. Many resembled lanterns of the day, consisting largely of a box with a handle and the lamp attached to the front. Some others were made to have a similar appearance to candles. It is possible that future developments of battery and Light-emitting diode LED technology will bring interesting new designs. For instance, one very small light that exists now in 2004 consists of a few LEDs with a switch, designed to be an endcap for a 9-volt battery. High-quality flashlights go for as much as several hundreds of dollars. Such flashlights are very advanced, using special batteries, have adjustable brightness levels, dive-depth waterproof ratings, interchangeable optics, and are very bright.

Other power sources
Since batteries can be a burdensome cost in developed countries, let alone in the third world, the development of self-powered torches is a welcome advance. Some use solar panels to recharge their batteries during the day. The clockwork torch has a spring with a winding handle, which powers the torch for a period of time. Some flashlights have an electrical generator built into it. Dynamo-powered flashlights have a winding crank connected to a stepper Electrical motor motor that feeds several diode bridges with their outputs connected in parallel feeding a field effect transistor that charges a capacitor that connects to one or more LEDs. Others generate electricity using electromagnetic induction. They use a strong permanent magnet that can freely slide up and down a tube, passing through a coil of wire as it does. Shaking the flashlight will charge a capacitor or a rechargeable Battery (electricity) battery that supplies a Current (electricity) current to a Lighting light source, typically a light-emitting diode or, more rarely, an incandescent light bulb. However, these types of flashlights have been reported to be ineffective because of the low energy.

Gallery
Image:Radio-Light.jpg|Radio-Light Image:Multi-Light.jpg|Multi-Light Image:LedFlashlight.jpg|Small LED light Image:Taschenlampe1.jpg|various types

See also
{{commons|Flashlight}} * Dyno torch * Maglite * Streamlight * Surefire

External links

Manufacturer sites

- Mag Instrument, Inc.
- Surefire tactical flashlights
- Streamlight flashlights
- Tektite LED and dive lights
- Pelican flashlights
- C Crane Company Homepage (distributors of Led Lenser and Coast LED flashlights)
- HDS Systems Inc. EDC Basic, EDC Ultimate and Action Light LED flashlights
- Arc Flashlights: Innovator in LED flashlights
- RevaNOS flashlights
- Maxa Beam Searchlights by Peak Beam Systems
- Dynamo flashlight
- Han's-lite LED flashlight
- Midnight Sun Innovations LLC

Hobbyist sites

- Flashlight-Forums.com (formerly Mr Bulk Forums)
- Flashlightreviews.com (Review website for lights)
- CandlePowerForums.com (forums for flashlight enthusiasts)
- Flashlight Museum
- Ledmuseum.org (Another review website for lights)
- PhotonForums (Smaller forums)
- FlashlightNews.org (Flashlight industry news) Category:Consumer goods Category:Lighting Category:Camping equipment Category:Hiking equipment de:Taschenlampe es:Linterna eléctrica nl:Zaklantaarn ja:懐中電灯 pl:Latarka elektryczna sv:Ficklampa

*** Shopping-Tip: Flashlight