LED Series Resistor Calculator

This tool is used to determine the value of current limiting resistors needed to connect multiple LEDs. Reset the calculator after each calculation.

Supply Voltage(V)

V

Forward Voltage(Vf)

Vf

Forward Current(I)

Ma

Resistor Value

Ω

Power

W

The LED Series Resistor Calculator is a simple yet essential tool for anyone working with LED circuits. LEDs are widely used in electronics projects and require a current-limiting resistor to prevent them from burning out. This calculator helps you determine the appropriate resistor value needed to safely power your LED using a given power supply voltage.

Why Use This Calculator?

The LED Series Resistor Calculator offers several key benefits:

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1. Prevents LED Damage: Helps protect your LED from excessive current, ensuring longevity and stable performance.
2. Quick and Accurate Calculation: Provides instant results, saving time and reducing the risk of calculation errors.
3. User-Friendly Interface: Intuitive design, making it easy to use for hobbyists, students, and professionals.
4. Supports Various LED Configurations: Suitable for single LEDs or multiple LEDs connected in series.
5. Free and Accessible: Available online at no cost, making it convenient for anyone needing quick resistor value calculations.

How to Use the LED Series Resistor Calculator

Using the calculator is straightforward:

1. Enter the Supply Voltage: Input the voltage of the power source (e.g., 5V, 9V, 12V).
2. Enter the LED Forward Voltage: Specify the forward voltage of the LED (typical values: Red LED ≈ 2V, Blue LED ≈ 3.2V).
3. Enter the Desired LED Current: Input the desired current for the LED (typically 20mA or 0.02A for standard LEDs).
4. Click Calculate: The calculator will display the required series resistor value in ohms (Ω).

Formula:

The value of the series resistor can be calculated using Ohm’s law:

Where:

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• R is the series resistor value (in ohms),
• V_S is the supply voltage (in volts),
• V_LED​ is the forward voltage of the LED (in volts),
• I_LED is the desired current through the LED (in amperes).

Example:

If the supply voltage is 9V, the LED forward voltage is 2V, and the desired current is 20mA (0.02A):

R = (9V−2V)/0.02A = 350 Ω

Applications of the LED Series Resistor Calculator

This calculator is useful in various scenarios:

1. LED Circuit Design: Helps in selecting the correct resistor to safely operate LEDs in DIY electronics projects.
2. Prototyping and Testing: Useful for quickly determining resistor values during prototyping and circuit testing.
3. Educational Use: Aids students in understanding the relationship between voltage, current, and resistance in LED circuits.
4. Home Automation Projects: Assists in designing LED indicators and displays for home automation systems.
5. General Electronics Projects: Essential for any project involving LEDs, whether for decorative purposes, indicators, or displays.