Magnetic Flux Density (B)

B from field strength, permeability, flux and area

Calculation
Quick Introduction

Magnetic flux density B describes magnetic loading in materials and cores. It is a key design parameter in electromagnets and transformers.

Schema:
1) choose material assumption (μr)
2) compute B from H or Φ/A
3) compare B against saturation limit
Formulas (MathJax)
\[B=\mu_0\mu_r H\]
\[H=\frac{B}{\mu_0\mu_r}\]
\[B=\frac{\Phi}{A}\]
Symbol Legend
  • \(B\): flux density [T]
  • \(\Phi\): magnetic flux [Wb]
  • \(A\): area [m²]
  • \(H\): field strength [A/m]
  • \(\mu_0=4\pi\cdot10^{-7}\,H/m\)


Examples
For \(\mu_r=2000\), \(H=120\,A/m\), \(B\approx0.302\,T\).
For \(\Phi=0.7\,mWb\), \(A=2\,cm^2\), \(B=0.35\,T\).
Summary

The calculator determines B from either material + field data or directly from flux and area for quick magnetic circuit checks.

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