There are several common methods out there for powering LED's. Why all the fuss? It boils down to this:1) LED's are very sensitive to the voltage used to power them (ie, the current changes a lot with a small change in voltage)2) The required voltage changes a bit when the power LED driver is put in hot or cold air, and also depending on the color of the LED, and manufacturing details. So there's several common ways that LED's are usually powered, and i'll go over each one in the following steps.PartsThis project shows several circuits for power LED driver for each of the circuits i've noted at the relevant step the parts that are needed including part numbers that you can find at www.digikey.com . in order to avoid much duplicated content this project only discusses specific circuits and their pros and cons. to learn more about assembly techniques and to find out LED part numbers and where you can get them (and other topics), please refer to one of my other power LED projects.