LED Tool · 007

Wrong resistor.
Dead LED.

Enter your supply voltage, the LED's forward voltage, and desired current to get the exact series resistor value and wattage rating you need.

LED Series Resistor Calculator

Supply Voltage V

LED Forward Voltage V

LED Current mA

Resistor Value — Ω

Nearest Standard Value —

Resistor Power Rating —

Formula: R = (Supply V − LED V) ÷ LED current. Always round up to the nearest standard resistor value to keep current at or below your target.

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