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LED Resistor Calculator

Work out the perfect series resistor to protect LEDs. Enter your supply voltage, LED forward voltage, and desired current to calculate the ideal resistor value.

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Inputs

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Manual run

Supply voltage (V)

LED forward voltage (V)

Desired LED current (mA)

Result

Ready when values are complete

Fill the required fields, then run the calculator to see the payoff.

Assumptions

Supply voltage (V): 5
LED forward voltage (V): 2
Desired LED current (mA): 20

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What this tool does

LED Resistor Calculator helps you work out the perfect series resistor to protect LEDs. Enter your supply voltage, LED forward voltage, and desired current to calculate the ideal resistor value.

What you get

LED Resistor Calculator produces a direct output in this page and keeps all processing on your device, with nothing uploaded to our servers.

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