What is Electricity?
Electricity is one of the most important discoveries in science and engineering. It powers our homes, computers, mobile phones, medical equipment, factories and nearly every electronic device we use every day. Understanding electricity is the first step towards learning electronics.
What is Electricity?
Electricity is the movement or presence of electric charge. In most electrical circuits, this charge is carried by tiny particles called electrons. When electrons move through a conductor such as a copper wire, an electric current is produced.
Although we cannot see electricity directly, we can observe its effects. Electricity can produce light, heat, motion, sound and magnetic fields.
Electric Charge
Everything around us is made of atoms. Each atom contains:
- Protons (positive charge)
- Neutrons (no charge)
- Electrons (negative charge)
The electrons in some materials can move freely. When these electrons move together through a conductor, electrical current is created.
Static Electricity
Static electricity occurs when electric charges build up on the surface of an object without continuously flowing.
Common examples include:
- Lightning
- A balloon sticking to a wall after rubbing it on your hair
- A small electric shock after walking on a carpet
Static electricity involves stored electrical charge rather than a continuous current.
Current Electricity
Current electricity is the continuous movement of electrons through a closed electrical circuit.
Examples include:
- Lighting your home
- Charging a mobile phone
- Running a computer
- Operating an audio amplifier
- Powering an Arduino project
Electronics mainly deals with current electricity.
Conductors and Insulators
Materials do not conduct electricity equally.
| Conductors | Insulators |
|---|---|
| Copper | Plastic |
| Aluminium | Rubber |
| Silver | Glass |
| Gold | Dry Wood |
Conductors allow electrons to move easily, while insulators resist the flow of electricity and are used for protection.
How Electricity Flows
Electricity only flows when there is a complete path called a closed circuit.
A simple electrical circuit consists of:
- A power source (battery or power supply)
- Connecting wires
- A load (lamp, resistor, motor or electronic circuit)
- A return path back to the power source
If the circuit is opened by switching off a switch or disconnecting a wire, current immediately stops flowing.
Electricity in Electronics
Unlike electrical power systems, electronics does more than simply deliver energy. Electronic circuits control, amplify, process and convert electrical signals using components such as:
- Resistors
- Capacitors
- Diodes
- Transistors
- Integrated Circuits (ICs)
- Microcontrollers
These components work together to create devices such as radios, televisions, computers, smartphones, robots and industrial equipment.
Key Points
- Electricity is the movement of electric charge.
- Electrons carry electrical current in most conductors.
- Static electricity is stored charge.
- Current electricity is moving charge.
- A complete circuit is required for current to flow.
- Electronics uses electricity to process information as well as provide power.