Rookie2:
Ok thank you.Please help me understanding this:
Lets say I want to connect some simple leds like these:
specs says: Max Peak Forward Current : 75mA
Yes but it's the max average forward current that will determine what you run your leds at. 20ma is
the current limit you should use for these leds set by the size of a series current limiting resistor between each output pin and the led.Does this means that with 6 or 7 leds I would be reaching the limit of the board?
Also the Mega documentation says each port delivers only 40ma so I don't get it.Each pins has an absolute max 40ma rating, and 30ma pin output current or less is safer value
to run the output pins at. So 7 leds running at 20ma is 140ma total, which is well within the boards +5vdc current capacity and each output pins rating.The key is it is up to you to manage the total current requirement for the complete project. If driving standard 20ma leds you do that by proper sizing of the current limiting resistors you have to have between the output pins and the leds.
Lefty