Digital output HIGH and LOW
Switch a digital output between 0V and 3.3V and watch the LED circuit respond.
LED current I = (VGPIO - Vf) / R
I = (3.3 V - 2.0 V) / 220 ohm = 5.9 mA
Current status OK
Current is within the typical 2-20 mA indicator LED range.
Controller Output pin: HIGH
220 ohm
GND
3.3 V
Pin voltage3.3 V
LED forward voltage2.0 V
Resistor220 ohm
LED current5.9 mA
LED stateON
Digital valueHIGH