DigiKey

This practice helped me to understand how the forward voltage affects the formula.

CHICAGO MINIATURE LIGHTING, LLC/ BLUE LED/ LED forward voltage: 4.9 V/ LED Current 20mA/ Resistor value: 5 Ohms

Lite-On Inc/ LED AMBER/ LED forward voltage: 2.1V/ LED current 10mA/ Resistor value: 290 Ohms

Lumex OptoComponents Inc /TORQUOISE LED/ LED forward voltage 3.2 V / LED current 20mA/ Resistor value: 90 Ohms

Kingbright Corp/ CYAN LED/ LED forward voltage 3.3V/ LED current 20mA/ Resistor Value: 85 Ohms

OSRAM Opto Semiconductors Inc/ LED GREEN/ LED forward voltage 2.85V/ LED current 5mA/ Resistor Value: 430 Ohms