LED Circuit Calculator
Resistor value from LED specs and supply voltage.
Inputs
Results
Exact Resistor (Ω)
150
Nearest E24 Resistor (Ω)
150
Actual Current (mA)20
Resistor Power (mW)60
Min Resistor Rating (W)0.13
LED Power (mW)40
Total Circuit Power (mW)100
Resistor Voltage Drop (V)3
How to Use This Calculator
- Enter your supply voltage (V) and the LED forward voltage (V) from the datasheet.
- Set the desired LED forward current (mA) and the number of LEDs wired in series.
- Review the calculated resistor value (Ω), nearest E24 standard resistor, and actual resulting current.
- Check resistor power dissipation (mW) and minimum wattage rating to ensure safe operation.
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