2.1 Basic Electrical Concepts

1. Voltage

Voltage, often referred to as electrical pressure, is the difference in electric potential between two points. It is measured in volts (V) and is the driving force that pushes electric current through a circuit. Think of voltage as the pressure that pushes water through a pipe in a plumbing system. The higher the voltage, the more forceful the push.

Example: A common household outlet provides 120 volts, which is sufficient to power most household appliances.

2. Current

Current is the flow of electric charge through a conductor. It is measured in amperes (A) and represents the rate at which charge flows. Current is analogous to the flow rate of water in a pipe. The higher the current, the more charge is flowing per unit of time.

Example: A typical light bulb draws about 0.5 amperes of current when connected to a 120-volt outlet.

3. Resistance

Resistance is the opposition to the flow of electric current in a material. It is measured in ohms (Ω) and depends on the material's properties and dimensions. Resistance is like friction in a water pipe that slows down the flow of water. High resistance means less current can flow, while low resistance allows more current to flow.

Example: A resistor with a value of 10 ohms will limit the current flowing through it according to Ohm's Law.

4. Power

Power is the rate at which electrical energy is transferred by an electric circuit. It is measured in watts (W) and is the product of voltage and current. Power can be thought of as the work done by the water in a pipe system, such as turning a waterwheel. The higher the power, the more work can be done.

Example: A 60-watt light bulb consumes 60 watts of power when connected to a 120-volt outlet, drawing 0.5 amperes of current.

5. Circuit

A circuit is a closed path that allows electric current to flow. It consists of a power source, conductors (wires), and a load (such as a light bulb or motor). For current to flow, the circuit must be complete, meaning there should be no breaks or interruptions. A circuit is like a complete loop of water pipes with a pump (power source) and a waterwheel (load).

Example: A simple circuit might include a battery, a wire, and a light bulb. When the circuit is complete, the light bulb lights up.

6. Ground

Ground is a reference point in an electrical circuit from which voltages are measured. It is also a path for excess current to return to the source, ensuring safety. Grounding is like having a drain in a water system that allows excess water to flow away safely. It prevents overpressure and potential hazards.

Example: In a household electrical system, the ground wire connects to the earth, providing a safe path for any stray current to flow.