What if there is a sudden power failure? Use candles to light up the room? Wait! It’s the old way. At present, with the advanced techniques, we can use backup lighting equipments such as a hand press flashlight to get rid of darkness. People can store electricity in backup lighting equipments beforehand or just insert batteries into hand press flashlight. In that way, people are able to light up the room in a safer way in comparison with using the candle for lightening.
A flashlight is a hand-held electric-powered light source. Usually the light source is a small incandescent light bulb or light-emitting diode (LED). Typical flashlight designs consist of the light source mounted in a parabolic or other shaped reflector, a transparent lens to protect the light source from damage and debris, a power source (typically electric batteries), and an electric power switch.
While most flashlights are hand-held, there are head or helmet-mounted flashlights designed for miners and campers and battery-powered lights for bicycles. Some flashlights are powered by hand-cranked dynamos or electromagnetic induction or are recharged by solar power.
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