A flashlight, which is called a torch in British Commonwealth countries, is a hand-held portable electric device which generates light. A conventional flashlight consists of an electric battery and incandescent light bulb.
With changes in technology and the rise of the age of semiconductors, flashlights also shifted from conventional light bulbs towards the use of LEDs. LEDs are light-emitting diodes (LEDs). By using proper material, these diodes can create lights of various colors.
LEDs have a high efficiency in term of power, up to 40LM/W, and they consume less power than normal lightbulbs. An LED flashlight needs less batteries than conventional flashlights. There are also batteryless flashlights which consist of an LED, a copper coil, a magnet, a rectifier and a capacitor. With the rotating magnet, a current is generated which is then stored in the capacitor. When the flashlight is started, the current stored in the capacitor will light up the LED.
Light emitting diodes are more durable. They have a longer lifetime. The expected lifetime for LEDs is nearly 10,000 hours. Unlike conventional flashlights, there is no delicate filament. Hence, LED flashlights can be used for many years. They can easily be used in rough and tough situations like mining. The energy wasted in terms of heat is also less than that of conventional flashlights.
LED technology is also useful in innovative flashlight designs like the headlamp. With the headlamp mounted on the helmet, the hands are free for work. The miners, firefighters, police and army find them very useful, as these flashlights can easily take more blows than conventional flash lights.