Definition
The generation of an electrical voltage in a conductor when it is exposed to a changing magnetic field. The voltage is produced whenever the conductor moves through a magnetic field, the magnetic field moves past the conductor, or the strength of the magnetic field changes. This is the principle behind generators, alternators, transformers, and magnetos.
Plain English
When a wire and a magnetic field move relative to each other, electricity is produced in the wire. Move the wire, move the magnet, or change the magnet's strength -- any of those will create voltage in the wire.
Context Anchor
Seen in aircraft electrical system discussions, especially when learning how alternators, generators, magnetos, and some sensors produce electrical output.
Derivation
From Latin 'inducere' meaning 'to lead in' or 'bring about.' The magnetic field 'leads in' or brings about a voltage in the wire without any direct physical contact. 'Electromagnetic' simply means involving both electricity and magnetism, which are two sides of the same underlying force.
Why Pilots Care
Magnetos depend on this process to produce ignition spark without relying on the aircraft battery.
Analogy
Think of moving a magnet near a coil like moving your hand through water: the motion creates a push. In electromagnetic induction, the changing magnetic field creates an electrical push in the wire.
Grounding Statement
Spin a coil of wire near a magnet and electricity flows in the wire -- that is electromagnetic induction at work, and it is how your aircraft's alternator keeps the battery charged.
Intuition Check
Electromagnetic induction is not engine induction. Here, “induction” means creating voltage by changing magnetism, not drawing air into an engine.
Example Sentence 1
The aircraft's alternator uses electromagnetic induction to convert the engine's mechanical rotation into electrical power for the avionics and battery.
Example Sentence 2
Even with a dead battery the engine starts because electromagnetic induction in the magneto supplies the needed voltage.