Flashlight
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- "Flashlight" is the NATO designation for the Yakovlev Yak-25 Soviet military jet.
A flashlight or torch is a hand-held portable electric spotlight. It is known as a flashlight mainly in the United States and as a torch in most Commonwealth countries.
A typical flashlight consists of a small electric lightbulb with associated parabolic reflector, powered by electric batteries, and with an 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 electric light. 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".
Recently, flashlights which use light-emitting diodes (LEDs) instead of conventional lightbulbs have become available. LEDs are far more efficient than, and use less power than normal lightbulbs, and so torches which use them have longer battery lifetimes. LEDs also survive sharp blows that often burn out conventional lightbulb models. Another innovation in flashlight design is the headlamp, 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.
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 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.
LedFlashlight.jpg
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.
See also
External links
Hobbyists who enjoy modifying and collecting flashlights enjoy a forum at Candlepower Forums (http://www.candlepowerforums.com) (also known as CPF).
- Surefire flashlights (http://www.surefire.com/)
- Streamlight flashlights (http://www.streamlight.com/)
- Mag Instrument, Inc. (http://www.maglite.com/)
- RevaNOS flashlights (http://www.revanos.com/)
- Han's-lite LED flashlight (http://www.flashlight.cn/)de:Taschenlampe