Definition
The strength of the magnetic field required to remove the residual magnetism from a magnetized material, returning it to a non-magnetized state.
Plain English
The amount of opposing magnetic pull needed to wipe out the leftover magnetism in a piece of metal.
Context Anchor
Seen in aircraft electrical and magnetism discussions, especially when studying generators, motors, and magnetic materials.
Derivation
From Latin coercere, meaning 'to restrain' or 'to force back.' The name fits because this force is what is required to push back against and cancel the magnetism already held in the material.
Why Pilots Care
Materials with high coercive force hold their magnetism well, which matters for permanent magnets in instruments and magnetos. Materials with low coercive force are easier to demagnetize, which matters when troubleshooting or servicing magnetic components.
Analogy
A strongly magnetized piece of metal is like a door that wants to stay partly open. Coercive force is the amount of push in the opposite direction needed to close it fully.
Grounding Statement
If a metal part is still magnetic after the original magnetic field is removed, coercive force is the opposite magnetic force needed to erase that leftover magnetism.
Intuition Check
Coercive force is not the pulling force of a magnet on another object. It is the opposing magnetic force needed to remove magnetism from the material itself.
Example Sentence 1
The alnico magnets used in the magneto have a high coercive force, so they retain their magnetism for many years of service.
Example Sentence 2
Higher coercive force in the magnet helps the directional gyro maintain stable indications despite vibration.