Example Data Table
| Method | Inputs | Computed Inductance | Design Use |
|---|---|---|---|
| Voltage and ripple | 12 V, 0.8 A, 25 µs | 375 µH | Switching regulator estimate |
| Energy and current | 4 mJ, 2 A | 2 mH | Energy storage check |
| Reactance and frequency | 31.4 Ω, 50 Hz | 100 mH | AC circuit sizing |
| Coil geometry | 120 turns, μr 2000, 1.5 cm², 8 cm | 6.79 mH | Magnetic core planning |
Formula Used
Inductance links voltage, current change, energy, frequency, and magnetic geometry. This calculator supports four practical engineering formulas for different design situations.
- Voltage-time method: L = V × Δt ÷ ΔI
- Energy method: L = 2E ÷ I²
- Reactance method: L = XL ÷ (2πf)
- Core geometry method: L = μ0 μr N² A ÷ l
Where μ0 is the permeability of free space, μr is relative permeability, N is turns, A is cross-sectional area, and l is magnetic path length.
How to Use This Calculator
- Select the method that matches your available circuit or core data.
- Enter values with the correct units in the visible fields.
- Click the calculate button to place the result above the form.
- Review converted values in H, mH, µH, and nH.
- Use CSV or PDF export to save your result summary.
- Compare the output with the example table for validation.
FAQs
1. Which method should I choose first?
Choose the method that matches your measured data. Circuit testing usually fits voltage and ripple. AC analysis fits reactance. Core design fits geometry inputs.
2. Why does the result change with units?
The physical result does not change. Only the displayed scale changes. The calculator converts all entered units to base values before solving.
3. Can I use this for switching converters?
Yes. The voltage-time method is especially useful for converter inductor sizing when voltage, ripple current, and switching interval are known.
4. What is inductive reactance?
Inductive reactance is the AC opposition created by an inductor. It increases with frequency and inductance, following XL = 2πfL.
5. Why does geometry need permeability?
Permeability describes how strongly the core material supports magnetic flux. Higher permeability generally increases inductance for the same turns and dimensions.
6. Does this include winding resistance?
No. This calculator estimates inductance only. Winding resistance, saturation, core loss, and temperature effects need separate checks during detailed design.
7. Is the energy formula safe for all currents?
Use it only for valid operating currents. If the current is near saturation or outside the component rating, the estimate may not match reality.
8. Can I save the output for reports?
Yes. After calculation, use the CSV button for spreadsheet work or the PDF button for a clean printable result summary.