The B–H Curve: What Permeability Really Means

Magnetise a piece of iron, remove the field, and some magnetism stays. Reverse the field and it takes effort to wipe it out. Plot field against magnetisation and you get a loop: the B–H curve, a material's magnetic fingerprint.

The video shows permeability as the slope, remanence and coercivity, soft versus hard magnetic materials, and why the area inside the loop is lost energy.

In this video

• Permeability as the slope of the curve
• Remanence and coercivity
• Soft materials for cores, hard materials for magnets
• Hysteresis loss and why transformers get warm