Outcome 4.1 Electrical Theory — Core Concepts for Mechanical, Electrical & Plumbing Systems

atom

The basic unit of matter, consisting of a nucleus containing protons and neutrons, with electrons occupying regions around it.

electron

A subatomic particle with a negative charge that is found outside the nucleus of an atom.

proton

A subatomic particle with a positive charge, found in the nucleus of an atom.

neutron

A subatomic particle with no charge, found in the nucleus of an atom.

electric charge

A fundamental property of particles, protons and electrons carry equal and opposite charge.

conductor

A material that allows electric charge to move easily through it.

insulator

A material that resists the movement of electric charge.

free electrons

Electrons that are loosely bound to atoms in a metal, allowing them to move freely and conduct electricity.

static electricity

An accumulation of electric charge on an object, often resulting in a spark when discharged.

current electricity

The continuous flow of electrons through a closed circuit due to a voltage source.

electric field

A region around a charged particle where other charged particles experience a force.

drift velocity

The slow, average velocity that charged particles (like electrons) attain due to an electric field.

potential difference

The voltage across two points in a circuit that causes current to flow.

Ohm's Law

A fundamental relationship in electricity stating that voltage (V) equals current (I) times resistance (R): $V = I \times R$.

power (P)

The rate at which electrical energy is transferred, calculated as $P = V \times I$.

electromagnetic induction

The process where a changing magnetic field induces an electric voltage in a conductor.

RMS (root mean square)

The effective value of an AC voltage or current, yielding the same power as DC in resistive loads.

battery

A device that converts chemical energy into electrical energy through electrochemical reactions.

generator

A device that produces voltage by moving a conductor through a magnetic field.

photovoltaic cell

A device that converts light energy directly into electrical energy.

thermoelectric generator

A device that generates voltage from a temperature difference across materials.

semiconductors

Materials that have electrical conductivity between that of conductors and insulators, whose ability can be modified.

voltage drop

The reduction in voltage across a component in a circuit due to resistance.

AC (alternating current)

Electric current that reverses direction periodically; voltage alternates as well.

DC (direct current)

Electric current that flows in one direction only, with constant voltage polarity.

electromagnet

A type of magnet created by electric current flowing through a coil of wire.

relay

An electrically operated switch that uses an electromagnet to open or close a circuit.

transformer

A device that uses electromagnetic induction to change voltage levels in AC circuits.