Dear FenderBender,I've been wondering for a while now how it is that with a 4.8v power source to an MR board that I won't need a resistor? If there is a resource (website, book, etc) That you suggest other than Electronic Formulas, Symbols & Circuits which Erv suggested and I can't seem to find. I just want to know for future builds and upgrades. Thanks for your help. Art