=== Formula ===
* calculation of resistance RD <math>\frac{U_r}{I} = \frac{VDD - U_{LR}}{I} = \frac{3.3V - 1.8V}{10mA}</math> = 150mA''' 150 ohm '''* calculation of resistance RD <math>\frac{U_r}{I} = \frac{VDD - U_{LR}}{I} = \frac{3.3V - 1.9V}{10mA}</math> = 140mA''' 140 ohm '''
= Layout =