Flash Light - By Shashank Soni

A flashlight is a portable hand-held electric light.

The source of the light is usually an incandescent

light bulb (lamp) or light-emitting diode (LED).

A typical flashlight consists of the light source mounted

in a reflector, a transparent cover (sometimes combined

with a lens) to protect the light source and reflector,

a battery, and a switch. These are supported and protected by a case.

The invention of the dry cell and miniature incandescent

electric lamps made the first battery-powered flashlights

possible around 1899. Today, flashlights use mostly

incandescent lamps or light-emitting diodes and run on disposable

or rechargeable batteries. Some are powered by the user turning

a crank or shaking the lamp, and some have solar panels

to recharge a battery.

In addition to the general-purpose hand-held flashlight, many

forms have been adapted for special uses. Head or helmet-mounted

flashlights designed for miners and campers leave the hands

free. Some flashlights can be used underwater or in flammable

atmospheres. Flashlights are used as a light source when in

a place with no power.