1. What is LED Forward Current?

LED forward current is the amount of electrical current flowing through an LED when it's operating. Proper current regulation is essential for LED longevity and brightness control.

2. How Does the Calculator Work?

The calculator uses the LED current formula:

Where:

• \( I \) — LED current (mA)
• \( V \) — Supply voltage (V)
• \( V_f \) — LED forward voltage (V)
• \( R \) — Current limiting resistor (Ω)

Explanation: The formula calculates the current through an LED by subtracting the LED's forward voltage from the supply voltage and dividing by the series resistance.

3. Importance of LED Current Calculation

Details: Proper current calculation ensures LEDs operate within their specified limits, preventing premature failure due to overcurrent while achieving optimal brightness.

4. Using the Calculator

Tips: Enter supply voltage in volts, LED forward voltage in volts, and resistance in ohms. All values must be valid (voltages > 0, resistance > 0).

5. Frequently Asked Questions (FAQ)

Q1: Why is a current limiting resistor necessary?
A: LEDs have nonlinear voltage-current characteristics. A resistor limits current to prevent thermal runaway and destruction of the LED.

Q2: What is typical forward voltage for LEDs?
A: Typically 1.8-3.3V depending on color and type. Red LEDs usually have lower V_f (~1.8-2.2V) while blue/white LEDs have higher V_f (~3.0-3.6V).

Q3: What happens if V is less than V_f?
A: The LED will not light up as there's insufficient voltage to overcome the forward voltage threshold.

Q4: How do I choose the right resistor value?
A: Use R = (V - V_f) / I, where I is your desired LED current (typically 10-30mA for standard LEDs).

Q5: Can I connect multiple LEDs with one resistor?
A: For series connection: R = (V - n×V_f) / I. For parallel connection, each LED should have its own resistor for proper current regulation.