Magnetic Field Strength (H)
H from turns/current/path length or from B
Calculation
Quick Introduction
Field strength H is the driving quantity in magnetic circuits and is mainly set by ampere-turns \(N\cdot I\).
Schema:
1) define geometry and winding
2) compute H at operating point
3) cross-check B and saturation
Formulas (MathJax)
\[H=\frac{NI}{l}\]
\[H=\frac{B}{\mu_0\mu_r}\]
\[H=\frac{\Theta}{l},\quad \Theta=NI\]
Symbol Legend
- \(H\): field strength [A/m]
- \(N\): turns [-]
- \(I\): current [A]
- \(l\): magnetic path length [m]
- \(\Theta\): magnetomotive force [A]
Examples
\(N=250\), \(I=1.2A\), \(l=180mm\) ⇒ \(H\approx1666.7\,A/m\).
\(B=0.35T\), \(\mu_r=2000\) ⇒ \(H\approx139.3\,A/m\).
Summary
The calculator determines H from coil data or material/flux density data for quick magnetic-circuit predesign.
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