Last updated: March 2, 2026

LED Current-Limiting Resistor

Formula

Every LED needs a current-limiting resistor to prevent burnout. The formula R = (Vs - Vf) / I calculates the correct resistance from your supply voltage, the LED's forward voltage, and the desired current. Choose the next higher standard resistor value for safety.

Common use cases:

  • LED circuit design
  • Arduino and Raspberry Pi projects
  • Indicator light installations

Frequently Asked Questions

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