Permanent vs. Temporary Magnets: Key Differences & Uses Explained
Permanent magnets keep their magnetic field indefinitely; temporary magnets act magnetic only when near another magnet or current.
People mix them up because fridge magnets look “always on” yet some gadgets turn off—it’s confusing when a screwdriver suddenly lifts screws but later drops them like nothing happened.
Key Differences
Permanent magnets use hard ferromagnetic alloys (e.g., neodymium), hold alignment without power, and cost more. Temporary magnets rely on soft iron that domains align only under external influence, then relax.
Which One Should You Choose?
Need steady grip? Go permanent. Need on-off control, like electric motors or cranes? Pick temporary coils or electromagnets to save energy and weight.
Examples and Daily Life
Speakers, fridge seals, and magnetic phone mounts use permanents. MRI coils, doorbell solenoids, and junkyard lifters switch temporary fields for safe release.
Can a permanent magnet lose strength?
Yes—heat above Curie temperature, strong opposing fields, or physical shock can demagnetize it.
Why does a screwdriver become magnetic sometimes?
Iron inside aligns with Earth or nearby magnets, making it a temporary magnet until disturbed.
Are electromagnets always temporary?
Yes; their field vanishes when current stops, though the core could retain slight residual magnetism.