LED resistor calculator
Enter the supply voltage, LED voltage and LED current.
Result
For 9 V supply and a 2 V LED at 20 mA, the resistor is 350 Ω.
Example
Find the series resistor needed for an LED.
For 9 V supply and a 2 V LED at 20 mA, the resistor is 350 Ω.
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Methodology
resistor = (supply voltage − LED voltage) / LED current.
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