[1] Fundamentals of Electricity

Electron Theory

according to this theory, all matter is composed of molecules which are made up of a combination of atoms that have a nucleus composed of protons and neutrons with electrons orbiting around it

Electron

negatively charged particle

Proton

positively charged particle

Neutron

neutral particle

Bound electrons

electrons that are bound in their orbit by the attraction of the protons

Free electrons

electrons in the outer band that became free of their orbit by the application of some external force such as movement through a magnetic field, friction, or chemical action

Electron flow

produced as free electrons move from one atom to the next

Electric current

produced when free electrons move from one atom to the next

Conductors

materials that permit many electrons to move freely

• copper

• silver

• aluminum

• zinc

• brass

• iron

examples of good conductors

Copper

most common material used for conductors and is relatively inexpensive

Insulators

materials that allow few free electrons

• plastic

• rubber

• glass

• mica

• ceramic

examples of good insulators

Semiconductor materials

can be used to manufacture devices that have characteristics of both conductors and insulators

Semiconductors

used in transistors, diodes, and other solid state electronic devices

Elements

often identified by the number of electrons in orbit around the nucleus of the atoms making up the element and by the number of protons in the nucleus

Positive charge

an electric charge caused by the lack of electrons because there are more protons than electrons

Negative charge

an electric charge caused by the excess of electrons

Coulomb’s Law

this law states that “unlike charges attract, like charges repel”

Electricity

flow of free electrons in a conductor from one atom to the next atom in the same general direction

Current

flow of electrons and is designated by the symbol “I”

Current

determined by the number of electrons that pass through a cross-section of a conductor in one second

6.24 × 10¹⁸

number of electrons in a single ampere

Electron flow

direction of current flow where electrons flow from negative to positive

Conventional current flow

direction of current flow where electrons flow from positive to negative

1. Direct Current (DC)

2. Alternating Current (AC)

Types of current

Direct Current (DC)

current that flows in a single direction

Alternating Current (AC)

current that alternates back and forth through the circuit

Voltage

energy (or work) required to move a unit charge through an element (current)

Volts (V)

unit used to measure voltage

Alessandro Antonio Volta

Italian physicist who invented the first voltaic battery and whom “volts” is named after

Voltage

it is the force that pushes electrons through a conductor

Resistance

ability of a circuit to resist or prevent the flow of current (electron flow)

Ohm’s Law

states that in an electrical circuit, the electric current that flows is directly proportional to the voltage applied to the circuit but inversely proportional to the resistance of that circuit

Series Circuit

a type of circuit of which the connection of components forms only one path of current from the positive terminal to the negative terminal

Voltage drop

voltage that can be measured in each resistor

Parallel Circuit

a type of electrical circuit in which components are connected across the same two points, creating multiple paths for the flow of electric current

Parallel Circuit

a circuit where each component has its own direct path to the power source

Series-Parallel Circuit

a combination of series and parallel connection of components; it is the most common type of connection in an electronic circuit