Fundamental Electronics - Chapter 1 - PDF

People's Democratic Republic of Algeria Ministry of Higher Education and Scientific Research Mohamed Khider University of Biskra Faculty of Sciences Exact and Life Sciences Department of Computer Science...

People's Democratic Republic of Algeria Ministry of Higher Education and Scientific Research Mohamed Khider University of Biskra Faculty of Sciences Exact and Life Sciences Department of Computer Science 1st Year engineer Module: Fundamental electronics Chapter 1 Main theorems for electrical network analysis Teacher: Dr.Boussabeur Mohamed Tayeb 2024\2025  What is electronics? 1)Electronics: it is a technical or engineering science that studies and designs structures that process electrical signals, electrical currents or voltages, carrying information or energy. Examples of electronic components:  Resistances  Capacitors  Inductances  Diodes  Transistors  Basic electronic components can be divided into two main families: 1) The Passive components: Components that do not increase the power of an electrical signal. This classification includes: - Capacitors - Resistors - Inductors 2) The Active components: An active component is a component that increases the power of a signal: - Transistors - Diodes - Triacs 2) Electrical networks: a network is a circuit composed of various components interconnected by connectors. Examples: The Symboles The name and Unit of the symbols Resistance (Ω) Inductance (H) Capacity (F) Direct voltage source (V) Direct current source (A)  Measuring instruments can be used to measure voltage and current in an electrical circuit: To measure current, use the ammeter.  The ammeter: it is the device used to measure current intensity. To measure voltage use voltmeter.  The voltmeter: it is the device used to measure voltage. Nb: The pinout of the voltmeter and the ammeter  A voltmeter is always connected in parallel with the device whose voltage you wish to measure.  An ammeter is always connected in series with the device whose current intensity is to be measured.  3) Ohm's law is a formula used to calculate the relationship between voltage, current and resistance in an electrical circuit.  Ohm's law is given by the equation : 𝑬 = 𝑹 ∗𝑰 This formula means Voltage = Current x Resistance 4) The power dissipated by the resistance: it is supplied by the source. The power P (in W) dissipated by the resistance is then: 𝑷 = 𝑬∗𝑰 = 𝑹 ∗ 𝑰𝟐  When the feed voltage increases, I increases and the power dissipated by R increases.  When the value of R increases, I decreases 5) The Nodes: A node is a point in a circuit where three or more wires meet. Example: Consider the above circuit: The circuit comprises: - Two nodes (A and B)  6) The Branches: it is a set of elements between two consecutive nodes.  Three branches : 7) The Meshes: a mesh is any closed path in a circuit that allows you to return to the starting point.  Series resistances: Resistances on the same branch. Resistances in series carry the same current I, but do not produce the same potential difference. 𝑅𝑒𝑞 = 𝑅1 + 𝑅2 + 𝑅3 +……… 𝑅𝑛  Resistances connected by the same pair of knots. Parallel resistance produce the same potential difference, but do not carry the same current. 1 1 1 1 1 = + + + …………………….. 𝑅𝑒𝑞 𝑅1 𝑅2 𝑅3 𝑅𝑛  Calculate the equivalent resistance : 1) Resistance in series 𝑅𝑒𝑞 =𝑅1 +𝑅2 𝑅𝑒𝑞 =700Ω 𝑅𝑒𝑞 =220+480 𝑅𝑒𝑞 =700Ω 2) Resistance in Parallel 1 1 1 = + 𝑅𝑒𝑞 𝑅1 𝑅2 1 1 1 = + 𝑅𝑒𝑞 220 480 𝑅𝑒𝑞= 150.86 Ω 𝑅𝑒𝑞= 150.86 Ω  The laws of Gustavo Robert Kirchhoff  In 1845, German physicist Gustav Robert Kirchhoff applied conservation of charge and conservation of energy to an electrical circuit. He derived two fundamental laws of electrical circuit analysis, known as Kirchhoff's law of nodes and Kirchhoff's law of meshes. ∑𝑰 = 𝟎 ∑ ∆𝑽 = 𝟎  𝑰: Current entering or leaving a node in a circuit.  ∆𝑽: Potential variation produced by an electrical component of a circuit.  Conventions on current : -A current entering a node is a positive current ( I > 0 ). - A current leaving a node is a negative current (I