1. What is LED Series Resistor Calculation?

LED series resistor calculation determines the appropriate resistor value needed to limit current through an LED when connected to a voltage source. This prevents the LED from burning out due to excessive current.

2. How Does the Calculator Work?

The calculator uses the LED resistor formula:

Where:

• \( R \) — Resistor value in ohms (Ω)
• \( V_s \) — Source voltage in volts (V)
• \( V_f \) — LED forward voltage in volts (V)
• \( I_f \) — LED forward current in amperes (A)

Explanation: The formula calculates the voltage drop across the resistor (Vs - Vf) and divides by the desired LED current to determine the required resistance.

3. Importance of Proper LED Resistor Selection

Details: Correct resistor selection is crucial for LED longevity and proper brightness. Too small a resistor allows excessive current, damaging the LED. Too large a resistor results in dim operation.

4. Using the Calculator

Tips: Enter source voltage in volts, LED forward voltage in volts, and LED forward current in amperes. Source voltage must be greater than LED forward voltage for proper operation.

5. Frequently Asked Questions (FAQ)

Q1: What is typical LED forward voltage?
A: Red LEDs: 1.8-2.2V, Green/Yellow: 2.0-2.4V, Blue/White: 3.0-3.6V. Check manufacturer datasheet for exact values.

Q2: What is typical LED forward current?
A: Standard LEDs: 20mA (0.02A), High-power LEDs: 350mA-1000mA or more. Always refer to LED specifications.

Q3: Can I use this for multiple LEDs?
A: For series connection, sum all Vf values. For parallel, calculate each branch separately with individual resistors.

Q4: What resistor power rating should I use?
A: Calculate power: P = (Vs - Vf) × If. Choose a resistor with at least 1.5 times the calculated power for safety margin.

Q5: What if calculated resistor isn't available?
A: Use the next higher standard resistor value to ensure LED safety. Standard values include 100Ω, 220Ω, 330Ω, 470Ω, 1kΩ, etc.