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Handle date differences, exact age, schedule math, and countdown planning from one set of utility tools.
💡 LED Resistor Calculator
Calculate the correct resistor value for your LED circuit
📏 Input Parameters
📊 Results
Required Resistor Value
500 Ω
Power Rating (Minimum)
0.20 W
📚 Understanding LED Resistors
Why Do LEDs Need Resistors?
LEDs require a current-limiting resistor to prevent excessive current flow that could damage the LED. The resistor drops the excess voltage and limits current to a safe level.
Formula
R = (Vs - Vf) / I
- R: Resistor value in ohms (Ω)
- Vs: Source voltage
- Vf: LED forward voltage
- I: LED current in amperes
Power Rating
P = (Vs - Vf) × I
Always use a resistor with a power rating at least 2x the calculated value for safety.
Typical LED Forward Voltages
- Red: 1.8-2.2V
- Green: 2.0-2.2V
- Blue: 3.0-3.4V
- White: 3.0-3.4V
- Yellow: 2.0-2.2V
🧭 Guided Journeys
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These grouped paths are designed to help you continue with the most common follow-up calculations in this category.
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