Recently, flashlights which use light-emitting diodes (LEDs) instead of conventional light bulbs 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 LS in 2001.
LEDs can be significantly more efficient at lower power levels, hence use less battery energy than normal light bulbs. Such flashlights have longer battery lifetimes, in some cases hundreds of hours, although the LED efficiency advantage diminishes at higher power levels. LEDs also survive sharp blows that often break conventional light bulbs.
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. For this reason higher-powered LED flashlights usually have metal bodies and can become warm during use.
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.
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 end cap 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.
Lantern is another important source of light while camping. Some lanterns are battery-powered and have simple light bulbs, but bright and efficient electric lanterns will employ a specialized power supply to operate a fluorescent type. They are easy to use and comparatively durable, but less bright than propane or liquid fuel lanterns. Depending on the design, these lanterns may use disposable batteries, rechargeable replaceable batteries, or permanently-installed rechargeable batteries and either require battery replacement, or if rechargeable and not constantly plugged in must be brought to full charge every few months by plugging in.
Some rechargeable fluorescent lanterns may be plugged in at all times and may be set up to illuminate upon a power failure, a useful feature in some applications. During extensive power failures (or for remote use), supplemental recharging may be provided from an automobile's twelve volt electrical system or from a modest solar powered charger.
Author Resource:-
Victor Epand is an expert consultant for http://www.CombatCloth.info/. CombatCloth.info carries the best selection of combat clothing, gear, and accessories on the market.
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