Name: circuit parts: branches, nodes, and loops
Uploaded: 2024-04-11T12:48:28.000Z
Duration: 1 min 14 s
Channel: JoVE

Un réseau électrique est un système d’éléments interconnectés, ne formant pas nécessairement un chemin fermé.
En revanche, un circuit, également un système interconnecté, doit contenir des chemins fermés.
Bien que tous les circuits soient des réseaux, tous les réseaux ne sont pas des circuits.
Basé sur la disposition des éléments, un circuit comprend des branches, des nœuds, des boucles et des maillages.
Une branche est un élément à deux bornes comme une résistance ou une source de tension. Un circuit ayant une source de tension, une source de courant et deux résistances se compose de quatre branches.
Un nœud relie deux branches ou plus et est représenté par un point. Si un court-circuit relie deux nœuds ou plus, ils constituent un seul nœud.
Une boucle est un chemin fermé qui traverse plusieurs nœuds sans croiser aucun nœud deux fois. Si la boucle comporte au moins une branche qui n’est pas partagée avec d’autres boucles, elle est indépendante.
Un maillage est un type de boucle qui ne contient aucune autre boucle.
Un réseau contenant b branches, n nœuds et l boucles indépendantes satisfait au théorème fondamental de la topologie de réseau.

terminologie des circuits

Circuit Terminology

Un réseau électrique est un système composé d'éléments interconnectés, tels que des résistances, des condensateurs, des inductances et des sources de tension ou de courant. Contrairement à un circuit, un réseau électrique ne forme pas nécessairement un chemin fermé. En d’autres termes, même si tous les circuits peuvent être considérés comme des réseaux en raison de leur nature interconnectée, tous les réseaux ne sont pas considérés comme des circuits. Un circuit, quant à lui, est également un système interconnecté d’éléments électriques mais doit contenir un ou plusieurs chemins fermés. Ces chemins fermés, ou boucles, permettent au courant de circuler en continu, rendant ainsi le fonctionnement du circuit possible. La structure d'un circuit peut être décomposée en plusieurs composants clés : branches, nœuds, boucles et maillages. Comprendre ces composants est crucial pour analyser et concevoir des circuits. Une branche représente un élément unique du circuit, comme une résistance, une source de tension ou une source de courant, connecté par deux bornes. Par exemple, un circuit comprenant une source de tension, une source de courant et deux résistances serait constitué de quatre branches. Les nœuds sont des points du circuit où deux ou plusieurs branches se croisent. Ils sont généralement représentés par un point dans les schémas de circuits. Si un court-circuit connecte plusieurs nœuds entre eux, ils deviennent effectivement un seul nœud. Une boucle dans un circuit est un chemin fermé qui traverse plusieurs nœuds sans traverser deux fois aucun nœud. Les boucles peuvent être indépendantes ou dépendantes. Une boucle indépendante possède au moins une branche qui n’est partagée avec aucune autre boucle. Un maillage, quant à lui, est un type particulier de boucle. Il s’agit d’un chemin fermé qui ne contient aucune autre boucle. Les maillages sont fondamentaux pour certains types d'analyse de circuits, tels que l'analyse de maillage, qui résout systématiquement les valeurs actuelles. Enfin, tous ces éléments sont liés entre eux par le théorème fondamental de la topologie des réseaux, qui stipule que pour un réseau contenant « b » branches, « n » nœuds et « l » boucles indépendantes, ces quantités sont liées par une formule spécifique, donnée par <img alt="Equation1" src="/files/ftp_upload/15067/15067_PT_Equation_1.svg" style="text-align: center; height: 14px;"> Comprendre cette relation est crucial pour l’analyse et la conception de réseaux et de circuits électriques.

Terminologie des circuits

Un réseau électrique est un système d’éléments interconnectés, ne formant pas nécessairement un chemin fermé.
En revanche, un circuit, également un ...

Education

Enseignement

JoVE Core

Electrical Engineering

Génie électrique

Unit 1

Unité 1

Basics of Electric Circuits

Les bases des circuits électriques

KEY TERMS AND CONCEPTS

TERMES ET CONCEPTS CLÉS

circuit parts: branches, nodes, and loops

Circuit parts like branches, nodes, loops, and meshes help describe how electrical networks work. An electrical network is a system of connected elements, such as resistors, capacitors, inductors, and voltage or current sources. Unlike a circuit, a network does not have to form a closed path.

A circuit is also made of connected electrical elements, but it must include one or more closed paths. These loops let current flow continuously, which is what makes the circuit operate. Because of this, every circuit is a network, but not every network is a circuit.

A branch is one element of a circuit with two terminals. A resistor, a voltage source, or a current source can each count as a branch. For example, a circuit with one voltage source, one current source, and two resistors has four branches.

Nodes are the points where two or more branches meet. They are usually shown as dots in circuit diagrams. If a short circuit connects several nodes, they act as one node.

A loop is a closed path that passes through several nodes without visiting any node twice. Some loops are independent, which means they have at least one branch not shared with another loop. A mesh is a special loop that contains no other loops inside it.

Meshes are important in mesh analysis, a method used to solve for current values in a circuit. These ideas also connect to the fundamental theorem of network topology. For a network with b branches, n nodes, and l independent loops, these values follow a specific relationship that is important for circuit analysis and design.

Circuit Parts: Branches, Nodes, and Loops

charge and current

Electric Charge in Circuits

Electric charge in circuits explains how charged particles behave in matter and how current is produced. Everyday static effects, like a wool sweater sticking to the body or a shock from a carpet, show charge in action. Charge is an inherent property of atomic particles and is measured in coulombs (C). Matter is made of atoms with electrons, protons, and neutrons. Electrons carry a negative charge (-e), and protons carry a positive charge (+e). These two charges have the same magnitude. An...

voltage

Voltage in Electric Circuits

Voltage in electric circuits is the energy needed to move electric charge between two points. It is also called electromotive force, or EMF. In most circuits, an external force such as a battery provides this energy for electron movement in a conductor. The voltage between points a and b is written as v_ab. It is defined as the work, or energy, needed to move a unit charge from point a to point b. In the equation, w is the energy in joules and q is the charge in coulombs. Voltage is measured...

power and energy

Circuit Power, Absorption, and Supply

Circuit power, absorption, and supply explain how much energy an element uses or delivers in an electric circuit. These ideas matter in electrical engineering because power and energy calculations help describe circuit behavior. A 100-watt light bulb, for example, emits more light than a 60-watt bulb, so wattage is a useful measure in real devices. Power is the time rate of expending or absorbing energy. It is measured in watts, written as W. The relation between power and energy uses the...

electric circuit elements

Circuit Elements: Passive, Active, and Linear

Circuit elements are the building blocks of an electric circuit. An electric circuit is the connection of these elements. In this context, circuit elements are often grouped by how they behave and whether they supply energy. One major group is passive elements. These elements do not generate energy. Common passive elements include resistors, capacitors, and inductors. The other group is active elements, which can generate energy. Generators, batteries, and operational amplifiers are typical...

circuit terminology

Circuit parts like branches, nodes, loops, and meshes help describe how electrical networks work. An electrical network is a system of connected elements, such as resistors, capacitors, inductors, and voltage or current sources. Unlike a circuit, a network does not have to form a closed path. A circuit is also made of connected electrical elements, but it must include one or more closed paths. These loops let current flow continuously, which is what makes the circuit operate. Because of this,...

independent and dependent sources

Circuit Source Symbols and Controls

Circuit sources in electrical circuits can be independent or dependent. They provide the power a circuit needs to operate. Independent voltage sources supply a fixed voltage, and independent current sources supply a fixed current. Their output does not change because of other parts in the circuit. These sources use standard symbols in circuit diagrams. An independent voltage source is shown with + and - signs to mark the potential difference. An independent current source is shown with an...

ohm's law

Resistance and Conductance in Circuits

Resistance and conductance help explain how electric current moves through a circuit. Resistors are basic circuit parts made from metallic alloys or carbon compounds. They are used to model how a material resists current and to control and regulate electrical power in a circuit. Ohm's law describes the link between voltage and current across a resistor. The voltage across a resistor is directly proportional to the current through it. The constant that sets this relationship is resistance.

kirchhoff's current law

Kirchhoff's Current Law at Circuit Nodes

Kirchhoff's Current Law explains how current behaves at a circuit node. A node is the point where two or more circuit elements meet. The law says the current entering a node equals the current leaving it. That balance follows the rule of charge conservation, which means electric charge is not lost at the junction. When applying KCL, currents entering the node are treated as positive and currents leaving the node are treated as negative. The currents can be added algebraically at the node, and...

kirchhoff's voltage law

Voltage Balance in Closed Circuit Loops

Kirchhoff's Voltage Law explains how voltage is balanced in a closed circuit loop. It is a basic rule in electrical engineering and comes from the idea of energy conservation. Energy can change form, but it cannot be created or destroyed. KVL states that the algebraic sum of all voltages around a closed path, or loop, is zero. In other words, the total voltage supplied in a loop equals the total voltage drop across the components in that loop. A loop can be traced clockwise or anticlockwise,...

voltage dividers

Series Resistors and Voltage Split

Series resistors split voltage across a circuit. In a series setup, resistors are linked one after another. The same current flows through each resistor in the chain. To analyze this behavior, Ohm's law is used to relate voltage, current, and resistance. Kirchhoff's voltage law says the voltages around a series loop add up to the source voltage. That means the current in the circuit equals the source voltage divided by the total resistance in series. The current value can then be used in Ohm's...

current dividers

Parallel Resistors and Current Division

Parallel resistors share the same two nodes, so each resistor has the same voltage across it. In this circuit setup, Kirchhoff's current law applies. The source current equals the sum of the currents through each branch. Ohm's law helps find the branch currents from the source voltage and the resistor values. The source current is equal to the source voltage times the sum of the reciprocals of the resistances. This makes it easier to calculate how current divides in the circuit. The current...

equivalent resistance

Delta-Wye Network Conversion

Delta-wye network conversion helps analyze resistor circuits that are not arranged in simple series or parallel paths. These three-terminal equivalent networks use the wye (Y), also called tee (T), and the delta (Δ), also called pi (π), as practical circuit models. These networks are useful in many circuit settings. They appear in three-phase electrical systems, electrical filters, and matching networks. They can also be used on their own or combined with more complex circuits. A delta...

design example: resistive touchscreen

Resistive Touchscreen Voltage Mapping

A resistive touchscreen uses voltage mapping to locate a finger touch on a mobile device. It is built from two metallic layers. The top layer is flexible, and the bottom layer is rigid. A narrow gap separates them, and the high resistance between the layers is an important part of the design. When a user touches the screen, the two layers meet at one point. That contact point is called the touchpoint. The touch lowers the resistance between the layers at that spot and changes the electrical...

key terms and concepts

Learn the key parts of circuits and networks, including branches, nodes, loops, and meshes, plus how these terms support circuit analysis.

Circuit Parts: Branches, Nodes, and Loops | JoVE K12

JoVE Core Electrical Engineering offers easy-to-understand animated videos that cover fundamental concepts of electric circuits along with circuit analysis techniques. It incorporates first-order and second-order circuits using operational amplifiers and circuit transformation concepts. The inclusion of practical design examples and real-world applications through scientist-in-action videos adds significant educational value, making complex concepts accessible.

electrical engineering

Circuit Parts: Branches, Nodes, and Loops

Description

Transcript

Tags