Introduction to Electronic Components (Resistors, Capacitors, Diodes) - SS2 Physics Lesson Note

Electronic components are fundamental building blocks used in electronic circuits to control and manipulate electrical signals. Three commonly used electronic components are resistors, capacitors, and diodes.

Resistors:

A resistor is a passive electronic component that restricts the flow of electric current in a circuit. It is typically made of a material with high resistance, such as carbon or metal. Resistors are used to control the amount of current or voltage in a circuit, limit current flow, and provide voltage drops. They are characterised by their resistance, which is measured in ohms (Ω). The resistance value determines the amount of current that flows through the resistor when a voltage is applied across it, according to Ohm's Law (V = I × R). Resistors are available in various types, including fixed resistors, variable resistors (potentiometers), and specialised resistors for specific applications.

Capacitors:

A capacitor is an electronic component that stores and releases electrical energy in the form of an electric field. It consists of two conductive plates separated by a dielectric material. When a voltage is applied across the plates, one plate accumulates a positive charge, while the other accumulates a negative charge. Capacitors are used in electronic circuits for various purposes, including energy storage, filtering, smoothing voltage fluctuations, and timing circuits. Capacitors are characterised by their capacitance, which is a measure of their ability to store charge. The capacitance is measured in farads (F) and can range from picofarads (pF) to microfarads (μF) or even higher. Different types of capacitors are available, including ceramic capacitors, electrolytic capacitors, tantalum capacitors, and film capacitors, each with specific properties and applications.

Diodes:

A diode is a semiconductor device that allows the flow of electric current in only one direction. It consists of a P-N junction formed by combining a p-type semiconductor (with excess holes) and an n-type semiconductor (with excess electrons). The diode allows current to flow easily from the p-side (anode) to the n-side (cathode) but blocks the flow in the opposite direction. Diodes are used for rectification (converting AC to DC), signal modulation, voltage clamping, and switching applications. They are characterised by their forward voltage drop (typically around 0.7V for silicon diodes) and their maximum reverse voltage (reverse breakdown voltage). Different types of diodes are available, such as signal diodes, rectifier diodes, Zener diodes, Schottky diodes, and light-emitting diodes (LEDs), each with specific characteristics and applications. These electronic components, along with others like transistors, integrated circuits, and inductors, form the basis of modern electronic systems. Understanding their properties, characteristics, and applications is crucial for designing and analysing electronic circuits. These components are combined in various configurations to create complex circuits that enable the functioning of electronic devices, ranging from small gadgets to large-scale industrial systems.