LED Key Chain Flashlights

[oneloneman]

Hello.  I am new to this forum (as you may have guessed) and I have a question about LED key chain flashlights.  On eBay I see 2 different LED key chain flashlights, one that appears to be a 5mm LED the other is a 10mm LED.  The 5mm has an output of 22000mcd (no beam angle given) while the 10mm has an output of 40 lumen with a 140⁰ beam angle.  So which is going to be the brightest (if the 5mm LED has a typical beam angle)? 

[justDIY]

Welcome to the boards!

40 lumen at 140 deg sounds like a power led, an older one - or perhaps underdriven.  It'll definitely be brighter than the one rated at a measly 22000mcd.  of course, that's assuming you can trust the description given!

Flashlights based on the current generation of technology are now becoming available in retail stores - I've see Cree and Luxeon parts personally, and another member of this forum has reported seeing Rebel based flashlights as well.  If this keychain light is only a few bucks, then it doesn't much matter.  Any more and I'd recommend buying something with at least 60 to 80 lumens of output.

[oneloneman]

Thanks!  What I know about LED's would not fill a thimble!