I currently have 60 LEDs in a parallel circuit. I am using 4 1.5v batteries as the source. The LEDs have a forward voltage of 3v-3.4v (8000mcd, wavelength 460nm).
My questions are: Can I just use one resistor at the start of the circuit (as I'd rather not de-solder all 60 LEDs and add them onto each one)? and if so.. What kind (ohm) of resistor should I buy? How, in future, would I figure all this out myself?