From the course: Learning Arduino: Foundations
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Deep dive: Calculating a current limiting resistor - Arduino Tutorial
From the course: Learning Arduino: Foundations
Deep dive: Calculating a current limiting resistor
- [Instructor] If you're a curious to know where we got the previous value of the resistor, or if your project requires a special kind of LED and you want to know how to determine the value of the resistor used, we use Ohm's Law, where voltage equals current times resistance. So when we rearrange the equation, the resistance equals voltage over current. Now, the minimum acceptable value of the resistor is determined using this equation where the resistor equals the voltage difference between the source and the voltage draw of the LED over the forward current of the LED. Since the voltage source is the Arduino pin, now the equation looks like this. The voltage includes the difference between the Arduino voltage from the pin and the specific LED voltage draw. So now I have the LED, I bought the LED and I need to know what resistor to use. So this is the data sheet of the specific LED that I'm using. Now, in order to know…
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