Rongge

High efficiency white LEDs have advanced to the point where they can replace glow bulbs and other light sources not only as indicators, but also for illumination. While many of the claims made about the LEDs' efficiency, light quality, lifetime and economy are mostly exaggeration, the truth is that for very low light levels they are now competitive. They have equal or slightly higher efficiency than a flashlight bulb, a longer lifetime, and are very much tougher. On the other hand, they are still far more expensive than a bulb, for a given light output. It follows that LEDs are almost ideal for very tiny, low power flashlights, in the less-than-one-watt category. But such a low power flashlight makes sense only if the whole flashlight is small and lightweight, and has a reasonable battery lifetime. But white LEDs require about 3.3 volts each, and typically some extra voltage is needed to provide room for current regulation! That's why most commercial LED flashlights use at leas...

High efficiency white LEDs have advanced to the point where they can replace glow bulbs and other light sources not only as indicators, but also for illumination. While many of the claims made about the LEDs' efficiency, light quality, lifetime and economy are mostly exaggeration, the truth is that for very low light levels they are now competitive. They have equal or slightly higher efficiency than a flashlight bulb, a longer lifetime, and are very much tougher. On the other hand, they are still far more expensive than a bulb, for a given light output. Cell LED Flashlight Circuit Diagram It follows that LEDs are almost ideal for very tiny, low power flashlights, in the less-than-one-watt category. But such a low power flashlight makes sense only if the whole flashlight is small and lightweight, and has a reasonable battery lifetime. But white LEDs require about 3.3 volts each, and typically some extra voltage is needed to provide room for current regulation! That's why most co...