LED flashlight hack

Popular Science has a simple hack for replacing a flashlight's bulb with bright white light-emitting diodes.

flashlightA flashlight … hacked to use three 2300-millicandela LEDs will be as bright as an incandescent and last 5 to 10 times longer. Of course you can add up to 20 LEDs (as long as they fit in the reflector) if you're planning to, say, man a lighthouse with the thing.

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