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I was connecting an LED to a microcontroller and needed to choose the values for the resistor. But first, I needed to calculate the forward voltage (Vf) of the LED. Later, I plan to drive some LED's with an Arduino and a MSP430 microcontroller. This video shows how to calculate the forward voltage of an LED. From there, you can choose a suitable resistor to limit the current and protect the LED's from being damaged.
