LED resistor calculator
One LED with a series resistor. Supply must exceed forward voltage. Results are ideal resistance and dissipation; allow component margins.
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One LED with a series resistor. Supply must exceed forward voltage. Results are ideal resistance and dissipation; allow component margins.
Worked example
Inputs
- Voltage (V): 5
- LED forward voltage (V): 2
- LED current (mA): 20
Results
- Required resistance: 150 Ω
- Resistor dissipation: 0.06 W
One LED with a series resistor. Supply must exceed forward voltage. Results are ideal resistance and dissipation; allow component margins.
Reviewed:Common uses
One LED with a series resistor. Supply must exceed forward voltage. Results are ideal resistance and dissipation; allow component margins.
BEHIND THE NUMBERSFormula & assumptions
R=(Vₛ−Vf)/(I/1000); P=(Vₛ−Vf)I/1000
One LED with a series resistor. Supply must exceed forward voltage. Results are ideal resistance and dissipation; allow component margins.