Name: finding voltage and impedance in circuit a
Uploaded: 2025-05-22T09:06:14.000Z
Duration: 1 min 18 s
Channel: JoVE

Das Stromverteilungssystem für Haushalte, das Verteilungsleitungen und Transformatoren umfasst, kann als Quellnetz betrachtet werden.
Im Inneren des Hauses können verschiedene Elektrogeräte als Lastimpedanzen dargestellt werden.
Der Satz von Thévenin vereinfacht dieses komplexe Verteilungssystem zu einer Thévenin-Ersatzschaltung.
Um die Thévenin-Ersatzschaltung zu finden, müssen zwei Parameter bekannt sein: die Thévenin-Spannung und die Thévenin-Impedanz.
Um den Prozess ihrer Bestimmung zu verstehen, betrachten Sie eine vereinfachte RLC-Schaltung, die an eine Spannungsquelle angeschlossen ist.
Um die Thévenin-Impedanz zu berechnen, ersetzen Sie die Spannungsquelle durch einen Kurzschluss und bestimmen Sie die äquivalente Impedanz der Schaltung.
Die Thévenin-Spannung ist gleich der Leerlaufspannung, was dem Spannungsabfall über den parallelen Zweig des Stromkreises entspricht.
Zunächst wird der Strom berechnet, der durch das geschlossene Netz der Schaltung fließt. Dann wird mit dem Ohmschen Gesetz der Spannungsabfall über den parallelen Zweig bestimmt, der die Thévenin-Spannung ergibt.
Verfügt die Schaltung über Quellen, die mit unterschiedlichen Frequenzen arbeiten, so müssen die Thévenin-Ersatzschaltung und die Impedanzen des Kondensators und der Induktivität für jede Frequenz getrennt bestimmt werden.

thévenin-Äquivalenzschaltungen

Als Primärnetz dient das Hausstromverteilungssystem, bestehend aus Verteilleitungen und Transformatoren. Elektrische Geräte innerhalb eines Haushalts können als Lastimpedanz dargestellt werden. Um dieses komplizierte Verteilungssystem zu vereinfachen, kann der Satz von Thévenin angewendet werden, um einen Thévenin-Äquivalenzschaltkreis zu erstellen. Wenn ein Wechselstromkreis in zwei Teile unterteilt ist (Kreis A und Kreis B), die durch ein einzelnes Anschlusspaar verbunden sind, wie in Figure 1 dargestellt. 
 <img alt="Figure1" src="/files/ftp_upload/15113/15113_PT_Figure_1.svg" style="text-align: center; height: 140px;"> 
 Figure 1: Schaltkreis in zwei Teile geteilt. 
 <img alt="Figure2" src="/files/ftp_upload/15113/15113_PT_Figure_2.svg" style="text-align: center; height: 150px;"> 
 Figure 2: Schaltkreis A durch seinen Thévenin-Äquivalentschaltkreis ersetzt 
 Das Ersetzen von Schaltkreis A durch seinen Thévenin-Äquivalenzschaltkreis (eine Spannungsquelle in Reihe mit einer Impedanz) ändert weder den Strom noch die Spannung eines Elements in Schaltkreis B (dargestellt in Figure 2). Die Werte der Ströme und Spannungen aller Schaltkreiselemente in Schaltkreis B sind gleich, unabhängig davon, ob Schaltkreis B mit Schaltkreis A oder seinem Thévenin-Äquivalent verbunden ist. Um das Thévenin-Äquivalenzschaltbild zu finden, sind zwei Parameter erforderlich: die Thévenin-Spannung und die Thévenin-Impedanz. Figure 3 zeigt einen offenen Stromkreis, der über die Anschlüsse von Stromkreis A angeschlossen ist, um die Leerlaufspannung Voc zu bestimmen, während Figure 4 zeigt, dass die Thévenin-Impedanz Zt die äquivalente Impedanz von Stromkreis A* ist. 
 <img alt="Figure3" src="/files/ftp_upload/15113/15113_PT_Figure_3.svg" style="text-align: center; height: 96px;"> 
 Figure 3: Thévenin-Äquivalenzschaltbild mit Voc. 
 <img alt="Figure4" src="/files/ftp_upload/15113/15113_PT_Figure_4.svg" style="text-align: center; height: 96px;"> 
 Figure 4: Thévenin-Äquivalenzschaltbild mit Zt. . 
 Stromkreis A* wird aus Stromkreis A gebildet, indem alle unabhängigen Spannungsquellen durch Kurzschlüsse und alle unabhängigen Stromquellen durch offene Stromkreise ersetzt werden. Im Allgemeinen kann die Thévenin-Impedanz Zt durch wiederholtes Ersetzen von Reihen- oder Parallelimpedanzen durch äquivalente Impedanzen bestimmt werden.

Thévenin-Äquivalenzschaltungen

Das Stromverteilungssystem für Haushalte, das Verteilungsleitungen und Transformatoren umfasst, kann als Quellnetz betrachtet werden.
Im Inneren des Hauses, ...

Education

Lehre

JoVE Core

Electrical Engineering

Elektrotechnik

Unit 1

Einheit 1

AC Circuit Analysis

Analyse von Wechselstromschaltungen

KEY TERMS AND CONCEPTS

ZENTRALE BEGRIFFE UND KONZEPTE

Th&#233venin Equivalent Circuits

finding voltage and impedance in circuit a

The household power distribution system can be simplified with Thevenin's theorem. In this system, distribution lines and transformers form the main network. Electrical appliances can be treated as load impedance, which makes the circuit easier to analyze.

An AC circuit can be split into two parts, circuit A and circuit B, with a single pair of terminals between them. Circuit A can then be replaced by its Thevenin equivalent circuit. That equivalent has a voltage source in series with an impedance.

Replacing circuit A with its Thevenin equivalent does not change the current or voltage of any element in circuit B. The values in circuit B stay the same whether it is connected to the original circuit A or to the Thevenin equivalent. This is why the method is useful for studying connected circuits.

Two values are needed to build the Thevenin equivalent circuit. The first is the Thevenin voltage, which is found from the open-circuit voltage across the terminals of circuit A. The second is the Thevenin impedance, Zt, which is the equivalent impedance of circuit A*.

To form circuit A*, all independent voltage sources are replaced with short circuits. All independent current sources are replaced with open circuits. Then series or parallel impedances can be combined repeatedly to find Zt.

Finding Voltage and Impedance in Circuit A

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Finding Voltage and Impedance in Circuit A

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