Unterschiede
Hier werden die Unterschiede zwischen zwei Versionen angezeigt.
Beide Seiten der vorigen Revision Vorhergehende Überarbeitung Nächste Überarbeitung | Vorhergehende Überarbeitung | ||
electrical_engineering_1:aufgabe_2.7.7_mit_rechnung [2021/10/08 22:26] – [Bearbeiten - Panel] tfischer | electrical_engineering_1:aufgabe_2.7.7_mit_rechnung [2023/07/17 13:36] (aktuell) – [Bearbeiten - Panel] mexleadmin | ||
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Zeile 2: | Zeile 2: | ||
<WRAP right> | <WRAP right> | ||
- | {{elektrotechnik_1: | + | {{elektrotechnik_1: |
</ | </ | ||
Given is the adjoining circuit with \\ | Given is the adjoining circuit with \\ | ||
- | $R_1=10 \Omega$\\ | + | $R_1=10 |
- | $R_2=20 \Omega$\\ | + | $R_2=20 |
- | $R_3=5 \Omega$\\ | + | $R_3=5 |
and the switch $S$. | and the switch $S$. | ||
- | 1. determine | + | 1. Determine |
<button size=" | <button size=" | ||
Zeile 18: | Zeile 18: | ||
</ | </ | ||
- | <button size=" | + | <button size=" |
First of all, it is a good idea to reshape the circuit so that the actual structure becomes visible. \\ | First of all, it is a good idea to reshape the circuit so that the actual structure becomes visible. \\ | ||
Zeile 29: | Zeile 29: | ||
Thus $R_3$ and $R_3$ can be combined to $R_{33} = 2 \cdot R_3 = R_1$, yielding a left and a right voltage divider. \\ | Thus $R_3$ and $R_3$ can be combined to $R_{33} = 2 \cdot R_3 = R_1$, yielding a left and a right voltage divider. \\ | ||
- | Now it is visible that in the left and right voltage divider the same potential is at the respective branch, or at the node K1 (green) and K2 (pink). | + | Now it is visible that in the left and right voltage divider, the same potential is at the respective branch, or at the node K1 (green) and K2 (pink). |
- | Thus, the total resistance can be calculated as $R_{ges} = (2 \cdot R_1)||(2 \cdot R_1)$. \\ | + | Thus, the total resistance can be calculated as $R_{\rm eq} = (2 \cdot R_1)||(2 \cdot R_1)$. \\ |
- | However, by symmetry, nodes K1 and K2 can also be short-circuited. Thus, $R_{ges} = 2 \cdot \left( R_1||R_1 \right)$ also holds. | + | However, by symmetry, nodes K1 and K2 can also be short-circuited. Thus, $R_{\rm eq} = 2 \cdot \left( R_1||R_1 \right)$ also holds. |
</ | </ | ||
- | <button size=" | + | <button size=" |
\begin{align*} | \begin{align*} | ||
- | R_{ges} &= 2 \cdot \left( 10 \Omega || 10 \Omega \right) = 10 \Omega | + | R_{\rm eq} &= 2 \cdot \left( 10 ~\Omega || 10 ~\Omega \right) = 10 ~\Omega |
\end{align*} | \end{align*} | ||
\\ | \\ | ||
</ | </ | ||
- | 2. what is the total resistance when switch $S$ is closed? | + | 2. What is the total resistance when switch $S$ is closed? |
- | <button size=" | + | <button size=" |
Due to symmetry, the potentials at K1 and K2 are equal. Thus, no current flows across resistor $R_2$ even when the switch is closed. \\ | Due to symmetry, the potentials at K1 and K2 are equal. Thus, no current flows across resistor $R_2$ even when the switch is closed. \\ | ||
So the resistance remains the same. \\ \\ | So the resistance remains the same. \\ \\ |