Go Down

Topic: Transistors and Resistors (Read 1 time) previous topic - next topic

fungus


On a side note - i thought arduino could supply 40ma through the output pins not 20ma as Henry_Best said? And up to an Amp (although i wouldn't) out of the 5v pin?


40mA is absolute maximum, not recommended for daily use.


Also what resistor should i have between the 5v arduino output and the led to stop it drawing more than 350ma? That is the real question for me!!!


The LED needs 1.4V, the resistor therefore has to dissipate the other 3.6V. Use Ohms law.
No, I don't answer questions sent in private messages (but I do accept thank-you notes...)


Nick Gammon

http://www.gammon.com.au/electronics

Go Up