LED Resistor Calculator

LED Resistor Calculator calculator can be used to calculate the appropriate resistor value for an LED based on supply voltage, LED forward voltage, and desired current.

Input Parameters

Calculation Results

Calculation Formula

Resistor Value (R) = (Supply Voltage - LED Forward Voltage) / Desired Current

Where:
Supply Voltage (V) - The voltage of the power supply
LED Forward Voltage (V) - The voltage drop across the LED
Desired Current (mA) - The current you want to flow through the LED

Result

LED Resistor Calculator Calculator Usage Guide

Learn how to use the LED Resistor Calculator calculator and its working principles

How to Use the LED Resistor Calculator

  1. Enter the supply voltage of your power source in volts (V).
  2. Enter the forward voltage of your LED in volts (V). This value is typically provided in the LED's datasheet.
  3. Enter the desired current for your LED in milliamperes (mA). This is the current you want to flow through the LED. A common value is 20mA for standard LEDs.
  4. Click the "Calculate" button to compute the appropriate resistor value and recommended power rating.

Working Principle

The calculator uses the formula:

R = (Vsupply - VLED) / Idesired

Where:

  • R is the resistor value in ohms (Ω)
  • Vsupply is the supply voltage in volts (V)
  • VLED is the LED forward voltage in volts (V)
  • Idesired is the desired current in amperes (A)

The power rating of the resistor is calculated to ensure it can dissipate the heat generated without overheating. It is recommended to use a resistor with a power rating higher than the calculated value for safety.