Enter Inductor Values
Formula Used
The calculator first converts frequency and inductance into base units. Frequency becomes hertz. Inductance becomes henries. It then calculates angular frequency using this formula:
ω = 2πf
Inductive reactance is calculated as:
XL = 2πfL
For a practical inductor with series resistance, total impedance magnitude is:
|Z| = √(R² + XL²)
The complex impedance form is:
Z = R + jXL
The phase angle is calculated as:
θ = tan⁻¹(XL / R)
If current is supplied, reactive power is estimated as Q = I²XL. If voltage is supplied, current is estimated as I = V / |Z|.
How to Use This Calculator
Enter the signal frequency first. Choose the correct frequency unit. Then enter the inductor value and its unit. Add series resistance if the inductor winding has measurable resistance. Use zero when you want ideal reactance only.
You may also enter voltage or current. These fields are optional. They help estimate current or reactive power. Press the calculate button. The answer appears above the form and below the header. Use the CSV button for spreadsheet records. Use the PDF button for a simple report.
Example Data Table
| Frequency | Inductance | Resistance | Reactance | Total Impedance |
|---|---|---|---|---|
| 50 Hz | 100 mH | 2 Ω | 31.416 Ω | 31.48 Ω |
| 60 Hz | 250 mH | 5 Ω | 94.248 Ω | 94.38 Ω |
| 1 kHz | 10 mH | 1 Ω | 62.832 Ω | 62.84 Ω |
| 10 kHz | 470 µH | 0.3 Ω | 29.531 Ω | 29.53 Ω |
Inductor Impedance Guide
What Inductor Impedance Means
Inductor impedance describes how strongly an inductor opposes alternating current. It is not fixed like simple resistance. It changes with frequency. A higher frequency creates more opposition. A larger inductance also creates more opposition. This makes inductors useful in filters, power supplies, radio circuits, motor drives, and signal shaping networks.
Why Frequency Matters
An inductor reacts to changing current. Slow changes create a small opposing voltage. Fast changes create a larger opposing voltage. That is why inductive reactance uses frequency in its formula. At zero frequency, an ideal inductor has no reactance. In direct current circuits, only winding resistance remains after the transient period ends.
Practical Series Resistance
Real inductors are not perfect. Their wire has resistance. Their cores can also create losses. This calculator lets you include series resistance. The result becomes a practical impedance estimate. The complex value uses the form R plus jXL. The resistance part consumes real power. The reactive part stores and returns magnetic energy.
Phase Angle and Circuit Behavior
In an inductive circuit, current lags voltage. The phase angle shows this delay. A nearly ideal inductor has a phase angle near ninety degrees. A lossy inductor has a smaller angle. This detail is important in alternating current design. It helps explain power factor, tuning, resonance, and transient response.
Using Optional Voltage and Current
The optional voltage field estimates current through the impedance. The optional current field estimates reactive power. These values help when checking component ratings. They also help compare coils at different frequencies. Always use safe design margins. Real circuits may include heating, saturation, parasitic capacitance, and tolerance changes.
Design Tips
Use measured inductance when possible. Many inductors have wide tolerance bands. Check the frequency range of the component. At very high frequency, parasitic capacitance can dominate behavior. The calculated value then becomes an approximation. For critical designs, compare this result with datasheet curves and lab measurements.
FAQs
1. What is inductor impedance?
Inductor impedance is the total opposition an inductor gives to alternating current. It includes inductive reactance and any series resistance.
2. What is inductive reactance?
Inductive reactance is the frequency-based opposition caused by inductance. It increases when frequency or inductance increases.
3. What is the main formula?
The main formula is XL = 2πfL. Here, f is frequency in hertz, and L is inductance in henries.
4. Why does impedance increase with frequency?
An inductor opposes changes in current. Faster current changes happen at higher frequencies, so the opposition becomes larger.
5. What does j mean in impedance?
The letter j represents the imaginary part of impedance. Engineers use it to separate reactance from normal resistance.
6. Can I include winding resistance?
Yes. Enter the winding or series resistance in ohms. The calculator then estimates practical total impedance magnitude.
7. What happens at direct current?
At direct current, ideal inductive reactance is zero after the transient ends. Only real winding resistance remains in steady state.
8. Is this result exact for every coil?
No. It is a strong estimate. Real coils have tolerance, core losses, capacitance, heating effects, and frequency limits.