** conduction voltage : VF = 1.8V
** average current : I = 20mA
* the datasheet of the orange LED (see pages 3) indicates that :
** conduction voltage : VF = 1.9V
** average current : I = 30mA
=== Formula ===
* calculation of resistance RD <math>\frac{U_r}{I} = \frac{VDD - U_{LR}}{I} = \frac{3.3V - 1.8V}{10mA}</math> = 150mA
* calculation of resistance RD <math>\frac{U_r}{I} = \frac{VDD - U_{LR}}{I} = \frac{3.3V - 1.9V}{10mA}</math> = 140mA
= Layout =