Electrical Fundamentals I Terms

Atom

Smallest unit of an element that retains its chemical properties, all materials are made up of atoms

Nucleus

Centre of an atom containing protons and neutrons

Molecule

A group of two or more atoms held together by chemical bonds, forming the smallest fundamental unit of a chemical compound.

Ion

Atom or Molecule that has gained or lost electrons, giving it an electrical charge

Compound

Substance containing two or more different elements chemically bonded together

Electron Shell

​Energy level surrounding the nucleus where electrons are found

Valence Shell

The outer most electron cell

Loosely Bonded Electrons

​Electron weakly attracted to the nucleus and easily removed

Valence Band

Energy band associated with the valence electrons, important in determining conductivity

Electrical Conductivity

Ability of a material to allow electrical current to flow

Conductor

Material that allows electrical current to flow easily (1 - 3 Electrons in valence shell & Valence and Conduction bands overlap)

Semiconductor

Material with conductivity between a conductor and a insulator (4 electrons in valence shell & Small band gap)

Insulator

Material that strongly resists electrical current (5 - 8 electrons in valence shell & Large band gap)

K

Maximum Electrons: 2

L

Maximum Electrons: 8

M

Maximum Electrons: 18

N

Maximum Electrons: 32

Electron Flow

Negative to Positive

Conventional Flow

Positive to Negative

Conduction Band

​Energy band where electrons are free to move through a material

Cuprous

Cu+ lost 1 electron

Cupric

Cu2+ Lost 2 electrons

Natural Copper

29 Protons and 29 Electrons

Cation

Positive

Anion

Negative

Ionisation

the process of forming ions by losing electrons

Element

Substance consisting of one type of atom

Alloy

Mixture of metals or a metal with another element

Ionic Bond

Electrons are transferred, forming oppositely charged ions (Metal > Non Metal)

Covalent

Atoms share electrons (Non-Metal > Non-Metal)

Metallic

Metal atoms are held together by shared, mobile electrons (Metal > Metal)

Electrolyte

​Liquid or gel containing Mobile ions that allow electrical current to flow

Electrolysis

Chemical decomposition caused by passing electrical current through an electrolyte

Dissociation

When a compound separates into charged ions when dissolved in water

Strong Electrolyte

​Compound that completely dissociates into ions in water, allowing electrical current to flow easily

Weak Electrolyte

Compound that only partially dissociates into ions in water, resulting in poor conductivity

Static Electricity

​An imbalance between positive and negative electrical charges in a material, causing charge to build up on its surface (Main Causes: Friction, Pressure & Separations)

Triboelectric Effect

​Generation of static electricity when two different materials come into contact and are separated transferring electrons

Factors Affecting Static Charge

Material

Force

Separation Rate

Realative Humidity

Relative Humidity

Amount of moisture in the air compared with the maximum it can hold at that temperature

Low Humidity

Greater Static Buildup

High Humidity

Reduced Static buildup

Triboelectric Series

List ranking materials according to their tendency to gain or lose electrons

Coulombs Law

The Electrostatic force between two charged objects is directly proportional to the product of their charges and inversely proportional to the square of the distance between them.

Electrostatic Force

Force of attraction or repulsion between electrically charged objects

Electrostatic Force formula

Increasing top = more force

Increasing bottom = less force

Electrostatic Charge Imbalance

Unequal distribution of positive and negative charges within or between materials

EMF

Electromotive Force

Ionic Soulution

Liquid containing freely moving positive and negative ions

Electrode

Conductor through which electrical current enters or leaves a liquid

Anode

the electrode where oxidation occurs (the loss of electrons)

Cathode

The electrode where reduction occurs (the gain of electrons)

Thermionic Emission

The release of electrons from a metal conductor when heated to a sufficiently high temperature

Edison Effect

The movement of electrons across a vacuum from a heated filament to a positively charged plate

Vacuum

A space containing no gas molecules to provide free electrons for conduction

Ampere (A)

Unit used to measure electrical current (coulombs per second)

Symbol: I

Current (A)

Symbol: Q

Charge (C)

Potential Difference

Difference in electrical potential between two points (measured in volts)

Electrical Potential

Voltage at a point measured relative to a reference point