Changes
/* Formula */
** average current : I = 30mA
=== Formula ===
* calculation of resistance R_LED_R \[begin{equation}<math>\frac{U_r}{I} = \frac{VDD - U_{LR}}{I} = \frac{3.3V - 1.8V}{10mA}</math>]\] end{equation} = ''' 150 ohm '''
* power dispersed by the resistance R_LED_R <math>\frac{R_LED_R^{2}}{I} = \frac{150 o ^{2}}{10mA}</math> = ''' 15 mW '''
