LED Resistor Calculator
Find the right resistor to safely power an LED.
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Formulas
R = (Vs - Vf) / IVs = Supply voltage, Vf = LED forward voltage, I = LED current
LED Forward Voltages
Red: 1.8-2.2V. Yellow: 2.0-2.2V. Green: 2.0-3.5V. Blue: 3.0-3.5V. White: 3.0-3.5V. Standard current: 20mA.