I have an Arduino Uno micro controller that operates at 5V and I'm doing some work with an LED. The positive leg of the LED has a 220ohm (1/4watt) resistor on it and goes into output pin 13 which produces 40ma @ 5V. My LED wants to have 2V @ 18ma. I'm not quite sure yet how to calculate the voltage and current after the 220ohm resistor yet and I really could use a little help out with the proper formulas. Thanks in advance for any commentary or answers...(adsbygoogle = window.adsbygoogle || []).push({});

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# Calculating Voltage and Current after resistor from an Arduino Uno.

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