How ELECTRICITY works - working principle

How Does Electricity Work?

Understanding Atoms and Their Structure

• Paul introduces the topic of electricity, emphasizing its importance in engineering and stating that the discussion will begin with atoms.

• Everything is composed of atoms, which vary based on their atomic structure. Atoms consist of three particles: neutrons (no charge), protons (positive charge), and electrons (negative charge).

• Electrons orbit the nucleus at high speeds in defined layers called orbital shells, similar to satellites around a planet. The number of protons, neutrons, and electrons determines the material's identity.

• The outermost shell, or valence shell, contains loosely bound electrons that can move between atoms. Conductors (like metals) allow electron flow while insulators (like glass and rubber) do not.

Circuits and Electron Flow

• When connected to a power source like a battery, free electrons in conductors can be forced to move in one direction through a closed circuit.

• A circuit is defined as the path for electron flow between positive and negative terminals; components like light bulbs can be added to this path to utilize electricity.

• Closed circuits allow electron flow while open circuits do not. Voltage acts as a pushing force for electrons, analogous to pressure in water pipes.

Key Electrical Concepts

• Voltage is measured in volts; one volt equals one joule per coulomb. A nine-volt battery provides nine joules of energy per group of flowing electrons.

• Current refers to the flow of electrons measured in amps; one amp equals one coulomb per second—approximately 6 billion billion electrons passing through per second.

Resistance and Its Effects

• Resistance restricts electron flow within circuits; it varies by wire length, thickness, material type, and temperature.

• Resistors are used intentionally in circuits to limit current for safety or functionality purposes (e.g., incandescent light bulbs generate heat/light due to resistance).

Magnetic Fields from Electric Currents

How Electromagnets and Transformers Work

Understanding Electromagnets

• The strength of a magnetic field can be increased by wrapping coils around an iron core, increasing the number of turns in the coils, or boosting the current passing through the circuit.

• This principle underlies how electromagnets function and serves as a foundation for induction motors. Further details on induction motors are available in another video.

Induction and Voltage Generation

• When a magnetic field crosses a coil of wire, it induces voltage due to electromotive force (EMF), which pushes electrons in a specific direction. If connected to a circuit, this EMF causes current flow.

• A transformer is created when one coil generates electricity that induces voltage into two closely placed coils without touching. This setup allows for electron flow if the secondary coil has a closed circuit.

Functionality of Transformers

• Transformers can increase or decrease voltage between primary and secondary coils by altering the number of coils on either side. This topic will be explored further in advanced discussions.

Capacitors: Basics and Functionality

• A capacitor separates positive and negative charges across two plates when connected to power, storing electrons within an electric field. Once power is interrupted, these charges release briefly before pairing again.

• While similar to batteries, capacitors are prevalent in nearly all circuit boards; more detailed coverage will follow in future videos.

Types of Current Electricity: AC vs DC

• There are two main types of current electricity: Alternating Current (AC), where current flows back and forth like ocean tides, and Direct Current (DC), which flows only in one direction.

• AC is commonly used for power sources such as home plug sockets, while DC is typically provided by batteries found in handheld devices.

Conversion Between AC and DC

• Power electronics allow conversion between AC and DC; this process enables solar panels (which produce DC power) to supply homes requiring AC power.