LED Wizard for Calculating Resistors and Drawing Schematics

This is a page I found extremely useful for calculating my resistors in LED circuits. You choose the number of LED's and the availiable source voltage and the program helps design the circuit for you. The nice thing about this page is that it also draws a sketch of the circuit* to build as a byproduct of the calculation:

(* be sure to click "wiring diagram")

http://led.linear1.org/led.wiz

To use the Wizard it might help to have the following data in lieu of the actual specifications of your LED's:

here's a table to help you make decent guesses:

For forward current you can use 20mA in most cases.

Color Voltage (Volts)
IR 1.5
red 2.0
orange 2.0
yellow 2.1
green 2.2
true green 3.3
blue 3.3
white 3.3
UV 3.3
blue (430 nm) 4.6