LED Resistor Calculator


About LED Resistor Calculator (Formula)

The LED Resistor Calculator is a tool used to determine the appropriate resistor value required to safely connect an LED to a power source, considering the LED’s forward voltage and desired current. It aids in designing LED circuits, preventing LED burnout, and ensuring optimal performance. The formula for calculating the resistor value involves considering the LED’s forward voltage and desired current.

Formula for calculating LED resistor value:

Resistor Value (in ohms) = (Supply Voltage – LED Forward Voltage) / LED Current

In this formula, “Supply Voltage” represents the voltage of the power source (e.g., battery, power supply), “LED Forward Voltage” represents the typical voltage drop across the LED (usually specified in datasheets), and “LED Current” represents the desired current flowing through the LED (also usually specified in datasheets). Subtracting the LED’s forward voltage from the supply voltage and then dividing the result by the LED current provides the resistor value in ohms.

For example, let’s say an LED has a forward voltage of 2.2 volts, the supply voltage is 5 volts, and the desired LED current is 20 milliamperes (mA). The resistor value would be calculated as follows:

Resistor Value = (5 V – 2.2 V) / 20 mA ≈ 140 ohms

This means that a 140-ohm resistor should be used to safely connect the LED to a 5-volt power source and achieve a current of 20 mA.

The LED Resistor Calculator simplifies the process of determining the appropriate resistor value for LED circuits, aiding hobbyists, engineers, and electronics enthusiasts in designing LED projects while ensuring proper LED operation and preventing damage. By inputting the LED’s forward voltage, desired current, and supply voltage, the calculator quickly provides the resistor value, allowing individuals to select the correct resistor and design LED circuits with confidence.

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