Calculator Inputs
Choose a model, enter values, and submit. The result appears above this form, directly below the header.
Example Data Table
| Case | Inputs | Formula | Magnetic Field Intensity |
|---|---|---|---|
| Conductor | I = 12 A, r = 0.05 m | H = I / (2πr) | 38.1972 A/m |
| Solenoid | N = 500, I = 1.2 A, l = 0.4 m | H = NI / l | 1,500.0000 A/m |
| Toroid | N = 300, I = 2 A, r = 0.08 m | H = NI / (2πrₘ) | 1,193.6621 A/m |
| Flux Density | B = 0.8 T, μr = 200 | H = B / (μ₀μᵣ) | 3,183.0989 A/m |
| Magnetic Path | N = 600, I = 1.5 A, lm = 0.3 m | H = NI / lₘ | 3,000.0000 A/m |
Formula Used
Long straight conductor: H = I / (2πr), where I is current and r is radial distance from the conductor center.
Long solenoid: H = NI / l, where N is turns, I is current, and l is magnetic length.
Toroid: H = NI / (2πrm), where rm is the mean magnetic radius.
From flux density: H = B / (μ0μr), where μ0 is the permeability of free space and μr is relative permeability.
General magnetic path: H = NI / lm, useful for magnetic circuits with known path length.
Derived values: B = μ0μrH and energy density u = BH / 2.
How to Use This Calculator
- Select the physical model that matches your problem: conductor, solenoid, toroid, flux-density conversion, or magnetic path.
- Enter the required geometric and electrical values. Keep units consistent, especially meters, amperes, tesla, and relative permeability.
- Choose your preferred output unit for the main result.
- Press the calculate button. The computed magnetic field intensity appears above the form, together with derived values and a Plotly graph.
- Use the CSV or PDF buttons to export the report for documentation, design checks, or study notes.
FAQs
1. What does magnetic field intensity measure?
It measures the magnetizing force produced by electric current or magnetomotive force along a path. It is commonly expressed in amperes per meter and is distinct from magnetic flux density.
2. What is the difference between H and B?
H describes the applied magnetizing force. B describes the resulting magnetic flux density inside the medium. They are linked through permeability, so the same H can produce different B values in different materials.
3. When should I use conductor mode?
Use conductor mode when you need the field intensity around a long straight current-carrying wire. Enter the current and the radial distance from the conductor center.
4. Why is relative permeability included?
Relative permeability lets the calculator convert between magnetic field intensity and flux density. Air is near one, while ferromagnetic cores can be much higher and produce much larger flux density for the same H.
5. Why does the solenoid model assume a long coil?
The long-solenoid equation assumes the internal field is nearly uniform and edge effects are small. Short coils deviate from this ideal behavior, so their actual field can differ near the ends.
6. Should toroid radius be inner, outer, or mean radius?
Use the mean magnetic radius for most engineering estimates. It better represents the average magnetic path length followed by the flux around the toroidal core.
7. Which output unit is best for reporting?
A/m is the standard SI unit and is usually best for engineering calculations. kA/m helps with larger values, while oersted is useful when comparing older magnetic literature.
8. Why does field intensity drop with distance for a wire?
Around a straight conductor, the magnetic field spreads over a larger circular path as distance increases. Because of that geometry, H decreases in inverse proportion to radial distance.