💡 LED Series Resistor Calculator
⚡ Output
ℹ️ About LED Series Resistor Calculator
LEDs (Light Emitting Diodes) are current-driven devices. Connecting them directly to a power source without a current-limiting resistor usually results in a destroyed LED. This tool calculates the exact resistance needed based on your supply voltage and the LED's specifications.
Common Forward Voltages (Vf):
- Red: 1.8V - 2.2V
- Green: 2.0V - 3.2V
- Blue/White: 3.0V - 3.6V
📖 How to use LED Series Resistor Calculator
- 1. Enter your supply voltage (e.g., 5V from an Arduino or 3.3V from an ESP32).
- 2. Enter the LED forward voltage (Vf) and the desired current (usually 20mA).
- 3. Select how many LEDs you are connecting in series.
- 4. The tool will calculate the required resistance and the closest standard E12/E24 resistor value.
❓ Frequently Asked Questions
Why does the resistor get hot?
Resistors convert excess voltage into heat. Check the 'Power Dissipation' result; if it's over 0.25W, you may need a higher wattage resistor (1/2W or 1W).
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