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LED Resistor
Choose a resistor for a single LED.
Live results
- Use E24 resistor
- 150 Ω
- Approximate current
- 20 mA
Adjust the circuit
Supply voltage
LED forward voltage
Desired LED current
Dial in the current
20 mA
Current indicator · 0–30 mA scale, not simulated brightness
Use 150 Ωat least 0.125 W
All calculated values
Live results
- Calculated resistance
- 150 Ω
- Use E24 resistor
- 150 Ω
- Approximate current
- 20 mA
- Resistor dissipation
- 0.06 W
- Suggested minimum rating (2× margin)
- 0.125 W
Formula and assumptions
R = (Vs − Vf) / I · Pr = I²ROne LED with a series resistor. The E24 recommendation rounds up. Current uses that standard value; the suggested rating is at least 2× calculated dissipation. LED Vf and resistor tolerances affect real current. Not a driver design for high-power LEDs.
Technical reference ↗