Electricity History: Key Figures and Milestones

History and Key Figures

• Ancient Egyptians noted observations of electric fish as early as 2750 BC
• Static electricity was observed by the Greeks around, 500 BC, specifically Thales of Miletus, who saw that rubbed amber attracted dust
• William Gilbert coined the term "electricity" from the Greek word "elektron" for amber

Key Milestones in Electricity

• 1600: Initial studies of electricity began
• 1751: Benjamin Franklin introduced terms like positive, negative, charge, battery, and electric shock
• 1765: James Watt's steam engine provided groundwork for modern electricity generation
• 1800: Alessandro Volta invented the first true battery
• 1831: Michael Faraday invented the electric dynamo, converting mechanical power into electromagnetic power

Key Inventors and Discoveries

• Benjamin Franklin introduced the concept of charge polarity (positive/negative)
• Franklin demonstrated lightning with his kite experiment, and invented the lightning rod
• Alessandro Volta invented the first electrochemical battery, the voltaic pile, enabling sustained electric current, in 1800
• Michael Faraday discovered electromagnetic induction in 1831, the principle behind electric generators and transformers
• James Clerk Maxwell developed a unified theory of electromagnetism, describing electricity, magnetism, and light variations of the same fundamental force
• Nikola Tesla designed the alternating current (AC) power system, invented the Tesla coil, and contributed to radio technology and wireless communication

Atomic Concepts

• Atoms consist of positively charged protons, negatively charged electrons, and neutral neutrons
• Electrons orbit the nucleus in shells
• An atom becomes electrically charged by gaining or losing electrons, forming ions
• Gaining electrons causes the atom to gain a negative charge, becoming a negative ion
• Losing electrons leads to the atom losing a negative charge, becoming a positive ion

Charging Methods

• Triboelectric Effect: Charging occurs through friction, as electrons transfer between objects rubbed together
• Static Electricity: Build-up of electric charge on a surface, often from the triboelectric effect

Conductors and Insulators

• Conductors allow electric current to flow easily due to freely moving electrons
• Insulators resist the flow of electric current because their electrons are tightly bound
• Good conductors offer less resistance to electron flow compared to poor conductors

Electrical Charges

• Positive and negative charges are the two types of charges
• The fundamental unit of electric charge is carried by a single proton or electron
• The total electric charge in an isolated system remains constant as per the Law of Conservation of Charge
• Charges can be transferred but not created or destroyed
• Like charges repel, while opposite charges attract

Properties and Uses of Electrical Charge

• Electric charge is responsible for electric forces and fields
• The principal of charge conservation is applied in numerous electronic devices and electrical systems

Charge and Electric Field

• An electric charge creates an electric field in the space around it
• The electric field exerts a force on any other charge within the field

Static vs. Current Electricity

• Static electricity involves the accumulation of electric charge at rest
• Current electricity is the flow of electric charge through a conductor

Electric Field Lines

• Electric field lines represent the direction and strength of an electric field

Properties of Electric Field Lines

• Field lines originate from positive charges and terminate on negative charges
• The density of field lines indicates electric field strength
• Field lines never cross each other

Electric Field of Single Charges

• Field lines radiate outward from a positive charge
• Field lines point inward toward a negative charge

Electric Field of Multiple Charges

• The electric field is the vector sum of the fields due to individual charges

Relationships Between Electric Field, Potential, Force

• Electric Field represents the force per unit charge
• Electric Potential is the potential energy per unit charge
• Electrostatic Force is the force between charges, given by Coulomb's Law
• The electric field is the negative gradient of the electric potential and the electrostatic force equals the product of the charge and the electric field

Electric Potential and Potential Difference

• Electric Potential is the work needed to move a unit of positive charge from a reference point to a specific point inside the field
• Electric Potential Difference is the difference in electric potential between two points and it is also known as voltage

Unit Conversions

• The charge of one electron is approximately 1.6020*10^-19 C
• To convert electrons to coulombs: Charge in Coulombs = Number of Electrons
• The number of Electrons Charge in Coulombs is 1.602 × 10^19C

Coulomb's Law

• Coulomb's Law describes the electrostatic force between two point charges
• The force is directly proportional to the product of the magnitudes of the charges and inversely proportional to the square of the distance between them
• F=k |q1q2|/r2
• F is the electrostatic force
• q1 and q2 are the magnitudes of the charges
• R is the distance between the charge
• K is Coulomb's constant