Basic electrical principles

Basic Electrical Principles

What is Electricity?

• Electricity is the flow of electrons from one place to another.
• The flow of electricity is called electric current.
• Current is measured in amperes (A)

Electrical Circuits

• An electrical circuit is a complete closed path through which electricity can flow.
• It is made up of components such as batteries, resistors, switches, and load devices (like a light bulb or motor).
• All circuits must have a power source (like a battery), a load device that uses the power, and conductors (like wires) to connect them.

Voltage, Current, and Resistance

• Voltage is the force that moves electrons, measured in volts (V).
• Current is the rate at which the electrons flow, measured in amperes or amps (A).
• Resistance slows down electron flow, measured in ohms (Ω).
• These three properties are related by Ohm’s Law: Voltage = Current x Resistance (V = I × R).

Type of Current

• There are two types of current: Direct Current (DC) and Alternating Current (AC).
• In a DC circuit, current flows in one direction only. Cars use DC.
• In an AC circuit, the current constantly changes direction. Houses use AC.

Basic Electrical Components

• Batteries store chemical energy and convert it to electrical energy.
• Resistors reduce current flow and are used to protect components in a circuit.
• Capacitors store electricity and release it when required.
• Diodes allow current to flow in one direction only.
• Transistors are used to amplify or switch electronic signals and power.
• Fuses protect circuits by breaking if the current is higher than its rated value.

Vehicle Electrical Systems

• Vehicles use a DC system powered by a 12-volt battery.
• The alternator charges the battery and powers the electrical system when the engine is running.
• The starter motor uses a large amount of current to turn the engine over.
• Other auxiliary systems powered by the battery include lighting, windscreen wipers, in-car entertainment systems, and climate control.