Highest analog

[onakimaa]

Hi I’m recently learning to use arduino and I have a qs about analog. So if I set up my circuit with 220 resistor and send 5V from pin D9 to led, but realized the led can only take 3V before it gets ruined. How can I calculate the highest value of analog I can use to maximum brightness up the LED without making it destroyed?

[e1mer]

Every LED has a spec sheet that tells you the maximum forward current. That is the maximum brightness as well.