FieldengElectrical & Power
LED Current-Limiting Resistor
Series resistor and dissipation for an LED or other voltage-dependent load.
Electrical & PowerEngineering Fundamentals
Series resistor and dissipation for an LED or other voltage-dependent load.
App id: ELEC-15. Reference version 1.0.
How to fill it
Fill the inputs. The tool shows the outputs.
On the tool screen, Calc is the working sheet. Presets stores values you reuse. Reference is the formula, assumptions, and provenance below.
Formula
R = (Vsupply − Vf) / I, P = I²RInputs
| Name | Unit |
|---|---|
| Supply voltage | V |
| Forward voltage | V |
| Desired current | mA |
Outputs
| Name | Unit |
|---|---|
| Resistance (hero result) | ohm |
| Resistor power | W |
| Recommended power rating | W |
Diagnose
This tool does not attach diagnose observations.
Assumptions
- Single series resistor. Forward voltage is treated as constant.
Provenance
- Recommended rating is the next common resistor wattage at least twice the dissipation.