Electromotive Force: Notes
Friction, light, heat, pressure, chemical reaction or magnetic action are all ways that electrons are freed. The free electrons will move away from the "Electron Moving Force" (EMF). A stream of free electrons form an electrical current.
| EMF | Method | Automotive Uses |
|---|---|---|
| Friction | Static, Walking Across Carpet | Electrostatic Field, Capacitor |
| Light | Photoelectric Cell, Light Controls | Headlamp and Mirror Sensors |
| Pressure | Piezoelectric, Speakers, Microphone | Knock and Side Impact Sensors |
| Chemical | Dry/Wet Cell Batteries | Primary Automotive EMF, Battery |
| Magnetic | Electromagnetic Induction, Coils | Secondary Automotive EMF, Generator |
The battery and the generator are the primary and secondary means by which free electrons are generated in automobiles.
The chemical reaction taking place in the battery creates an Electromotive Force (EMF) that provides us with the positive ions and negative ions.
The generator through magnetic induction is our other source of free electrons. (Positive and negative ions)
The positive ions collect at the positive battery terminal and the negative ions collect at the negative battery terminal.
The positive and negative ions provide no energy unless a path between them is established. This path is normally in the form of a load (e.g. bulb, electric motor or other electrical consumer) placed across the positive and negative terminals of the battery either directly or through wires.