LED spotlights

[nemo]

ODD name for a lens! :o)

[G Cadman]

Kind of, except an OOD also uses internal refraction. ;-)

[John]

I'm not a physicist but isn't that what lenses use? :-)

[Mike C]

Just as an aside, LED's have been used for boat navigation lights, where you would think they'd be ideal - it's really hard to change a bulb at the top of a mast - but in reality, they haven't become very popular. Nav lights have to be seen over a wide angle, so an array of LEDs pointing in different directions is necessary. They drop about 0.65V-0.8V, so they are run about

6 or 8 in series, with a resistor to drop the rest of the voltage, so the efficiency is fair, but when the total current for all LED's is worked out, it comes to more than that required for a bulb. It has to be said, though - they are a lot more reliable!

Mike.