A LED can only absorb a certain amount of current before it is damaged, and this varies depending on the type. Attach a resistor in series with it for protection or current limitation.

With the help of this LED resistor calculator, technicals can easily determine the ideal resistance value for the LED application.

A simple LED circuit’s resistor value can be determined by calculating the voltage drop from the voltage at the source and applying Ohm’s Law.

**LED Resistor Formula:**

**R = (V – V _{F})/I_{F}**

where:

V is the source voltage, measured in volts (V),

V_{F} is the voltage drop across the LED, measured in volts (V),

I_{F} is the current through the LED measured in Amperes (Amps/A), and

R is the resistance, measured in Ohms (Î©).

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