how do you calculate the LEDs proper resistor? And here's
another site: http://home.cogeco.ca/~rpaisley4/LEDcalc.html In
general, you want a few milliamps (maybe 2 - 20 mA?) running
thorugh your LED. The higher the current, the brigher the LED
will be, but the faster it will burn out. To calculate the
current passing through your LED you can use Ohm's Law: I = (V -
LED voltage drop)/R Typically LEDs have a voltage drop of
between 1 and 3 V, depending on their color (the higher the
energy of their color, the bigger the voltage drop). As long as
you're in the low milliamp range, you can always try a current
and see how bright your LED is (assuming it's visible and not
IR, of course), then adjust the resistor accordingly if it seems
too bright or dim.