[QUOTE=mklotz;194134]LEDs are used often enough in home projects that it's worth a short tutorial on determining the proper resistor to be used with one.

The breakdown voltage of an LED (Vb) varies with color. This chart shows ranges of that voltage...


Marv,

A bit of poking around for infrared LEDs (which I occasionally use in isolation applications) yields Vb around 1.9v.


Bob