LED Series Resistor Calculator

LED Series Resistor Calculator

An LED Series Resistor Calculator helps you determine the optimal resistor value needed to safely operate an LED with a given power supply voltage. LEDs require a current-limiting resistor to prevent excessive current flow, which can damage or destroy the LED.

How It Works

The required resistor value is calculated using Ohm’s Law: R=(Vsupply−Vforward)/Iforward​​

Where:

  • R = Resistor Value (Ω)
  • Vsupply = Supply Voltage (V)
  • Vforward​ = LED Forward Voltage (V)
  • Iforward = LED Forward Current (A)

Additionally, the power dissipated by the resistor is calculated as: P=I2×R

Where:

  • P = Resistor Power (W)

Why Use a Resistor?

  • Protects the LED from excessive current.
  • Ensures consistent brightness and longer LED lifespan.
  • Helps match different supply voltages to LED operating requirements.