# Electrical and electronic components, devices, and systems

## Basics of Electricity

• Electricity is a form of energy resulting from the existence of charged particles like electrons and protons, either static or moving.
• Current (I) is the amount of charge passing through a specific point in a circuit per second. It is measured in Amperes (A).
• Voltage (V) is the electrical force that drives the current around the circuit. It is measured in Volts (V).
• Resistance (R) is opposition to the flow of current and is measured in Ohms (Ω).
• The relationship between these three factors is given by Ohm’s Law, which states that V=IR.

## Electrical and Electronic Components

• Resistors limit the flow of current in a circuit. The higher the resistance, the less current flows for a given voltage.
• Capacitors store electric charge. They are used in filtering, tuning circuits and time-delays.
• Inductors store energy in their magnetic field and are commonly used in tuned circuits and for power supply smoothing.
• Diodes allow current to flow in one direction only.
• Transistors are devices that can amplify an electrical signal or act as an electronic switch.
• Integrated Circuits (ICs) contain many transistors, resistors, diodes and other components, offering complex functions in a small package.

## Devices and Systems

• Power Supplies convert electricity from one form to another - often from AC to DC.
• Oscillators generate a repetitive signal, usually a sine wave or square wave.
• Amplifiers increase the magnitude of a signal.
• Filters remove or enhance frequencies in electronic signals.
• Logic gates are fundamental building blocks of digital circuits.

## Circuits and Systems

• Series circuit: Components are connected end-to-end so the same current flows through each one.
• Parallel circuit: Each component is separately connected to the power source, so the voltage is the same across each one.
• Complex (Mixed) circuit contains combinations of series and parallel connections.
• Digital Systems: Utilise digital signals that represent binary numbers, zeros and ones.
• Analogue systems: Utilise signals that are a continuous waveform.
• A Transducer converts one form of energy to another - for example, a microphone converts sound waves into electrical signals.
• Relays and Contactors are electrically controlled switches used for controlling large power loads.

## Safety Measures

• Understand the Hazard and Risk Assessment.
• Use of Personal Protective Equipment (PPE) for safety.
• Awareness of Electrical Isolation to avoid electric shock.
• Knowledge of Emergency Procedures in case of any unfortunate incident.