basic

LED Forward Voltage & Current-Limit Resistor

R = (Vs − Vf) / If — series resistor to protect an LED.

Calculates the series current-limiting resistor value needed to protect an LED from a supply voltage given its forward voltage and desired current.

Daniel Oh By Daniel Oh
Published Last reviewed 1 min read

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Formula

R = (V_supply − V_forward) / I_forward

In depth

Calculates the series current-limiting resistor value needed to protect an LED from a supply voltage given its forward voltage and desired current.