1. What is the LED Resistor Calculator?

The LED Resistor Calculator helps determine the appropriate resistor value needed to safely operate an LED with a given power supply. It prevents LED damage by ensuring the correct current flows through the circuit.

2. How Does the Calculator Work?

The calculator uses Ohm's Law formula:

Where:

• \( R \) — Resistor value in ohms (Ω)
• \( V_{supply} \) — Supply voltage in volts (V)
• \( V_{led} \) — LED forward voltage drop (V)
• \( I \) — Desired current through LED in amperes (A)

Explanation: The resistor limits current to protect the LED from excessive current that could damage it.

3. Importance of Proper Resistor Selection

Details: Choosing the correct resistor is crucial for LED longevity and brightness control. Too small a resistor can burn out the LED, while too large a resistor will make it too dim.

4. Using the Calculator

Tips: Enter supply voltage in volts, LED forward voltage in volts, and desired current in amperes. Typical LED currents range from 0.01A to 0.03A (10mA to 30mA).

5. Frequently Asked Questions (FAQ)

Q1: What is LED forward voltage?
A: Forward voltage is the voltage drop across the LED when current flows through it. It varies by LED color and type (typically 1.8V-3.6V).

Q2: What current should I use for my LED?
A: Most standard LEDs operate at 20mA (0.02A), but check your LED's datasheet for specific recommendations.

Q3: Can I use this calculator for multiple LEDs?
A: For series connections, sum the LED voltages. For parallel connections, calculate resistors for each LED separately.

Q4: What if my calculated resistor isn't a standard value?
A: Use the next higher standard resistor value to ensure the LED doesn't receive too much current.

Q5: Do I need to consider resistor power rating?
A: Yes, calculate power dissipation: P = I² × R. Choose a resistor with at least twice the calculated power rating for safety.