Electromagnetism
principle · 1820 · Industrial Revolution
An electric current creates a magnetic field (Ørsted’s experiment), and a field acts on a current.
Where it is used
- Electric motor — is used in. Current in the windings creates a magnetic field that turns the rotor.
- Electrical telegraph — is used in. A telegraph receiver is an electromagnet that attracts an armature.
- Loudspeaker — is used in. A coil carrying current in the field of a permanent magnet moves the diaphragm.
- Vibration motor — is used in. Like any electric motor, it turns thanks to electromagnetism.
- Maglev — is used in. Electromagnets hold and move the train.
- Tokamak — is used in. Magnetic fields confine the plasma.
- Circuit breaker — is used in. An electromagnetic trip.
- Electromagnet — is used in. Current creates a magnetic field.
- Cathode-ray tube — is used in. The beam is deflected by a magnetic field.
- Electronic ink — is used in. The pigment moves in an electric field.
- Galvanometer — is used in. The needle is deflected by the field of the current.
- Ammeter — is used in. Current in the coil creates a magnetic field, and the needle turns further the larger the current.
- Hollerith tabulator — is used in. The counters click with electromagnets.
- Hub motor — is used in. A hub motor is an electric motor.
- Starter motor — is used in. A starter is an electric motor.
- Servomotor — is used in. A servo is an electric motor with feedback.
- Multimeter — is used in. Current in a coil deflects the needle.
History: what it evolved from and what it influenced
- Electromagnetic induction — evolved into. Faraday looked for the reverse of Ørsted’s discovery and found induction.
- Magnetism — evolved from. Ørsted linked magnetism with current.