** conduction voltage : ULG = VF = 2.2V
** average current : I = 30mA
=== Formula ===
* calculation of resistance R_LED_R :
R_{LED_R}=\frac{U_r}{I}=\frac{VDD-U_{LR}}{I}=\frac{3.3V-1.8V}{10mA}
</math>
= ''' 150 ohm '''
* power dispersed by the resistance P_R_LED_R :