LED flashlights or "LED torches" (as they are called in Britain) are hand-held flashlights that use light emitting diodes (LEDs) as opposed to the older technology of incandescent light bulbs. In 1992, bright blue LEDs made from GaN were invented by Shuji Nakamura in Japan. White LEDs were then made based on the technology used in blue LEDs. LEDs have a high light to power effiency, up to 40LM/W. They are much more durable than conventional lightbulbs. The expected lifetime for LEDs is up to 100,000 hours. These advantages have made the LED flashlight popular. The voltage to drive a LED is 3.0V to 3.6V. So a step up circuit should be used in LED Flashlight using 1 or 2 1.5V dry battery.