LED Resistor Calculator

📖 Frequently Asked Questions (FAQ)

1. Why do LEDs need a resistor?

LEDs have very little internal resistance. Without a resistor to limit the flow of electricity, they would draw too much current from the power source, causing them to burn out almost instantly. This component is called a current-limiting resistor.

2. What is LED Forward Voltage (Vf)?

Forward Voltage is the amount of voltage the LED requires to turn on and produce light. It's the "voltage drop" across the LED when current is flowing through it. This value varies by the LED's color (e.g., a red LED is typically ~2.0V, while a blue one is ~3.2V).

3. What is LED Forward Current (If)?

Forward Current is the ideal, recommended current the LED needs to operate at its intended brightness without being damaged. This is typically around 20 milliamperes (mA) for standard 5mm LEDs.

4. How is the LED resistor value calculated?

The value is calculated using Ohm's Law. The formula is: Resistor (Ω) = (Supply Voltage - LED Forward Voltage) / LED Forward Current (in Amps).