Unterschiede
Hier werden die Unterschiede zwischen zwei Versionen angezeigt.
Beide Seiten der vorigen Revision Vorhergehende Überarbeitung | Nächste Überarbeitung Beide Seiten der Revision | ||
electrical_engineering_1:aufgabe_7.2.6_mit_rechnung [2023/02/11 23:08] mexleadmin |
electrical_engineering_1:aufgabe_7.2.6_mit_rechnung [2023/03/09 13:36] mexleadmin |
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Zeile 5: | Zeile 5: | ||
The circuit shown right is given with the following data: | The circuit shown right is given with the following data: | ||
- | * $U = 10 V$ | + | * $U = 10 ~V$ |
- | * $I = 4 mA$ | + | * $I = 4 ~mA$ |
- | * $R_1 = 100 \Omega, R_2 = 80 \Omega, R_3 = 50 \Omega, R_4 = 10 \Omega$ | + | * $R_1 = 100 ~\Omega, R_2 = 80 ~\Omega, R_3 = 50 ~\Omega, R_4 = 10 ~\Omega$ |
- | * $C = 40 nF$ | + | * $C = 40 ~nF$ |
- | At first the voltage drop on the capacitor $u_C=0$ and all switches are open. The switch S1 will be closed at $t=0$. | + | At first the voltage drop on the capacitor $u_C = 0$ and all switches are open. The switch S1 will be closed at $t = 0$. |
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- | The electrical components $R_1$, $R_2$ und $C$ are connected in series with a source $U$. The time constant $\tau$ is therefore: \begin{align*} \tau &= (R_1 + R_2) \cdot C \\ \tau &= 180 \Omega \cdot 40 nF \end{align*} | + | The electrical components $R_1$, $R_2$ und $C$ are connected in series with a source $U$. The time constant $\tau$ is therefore: \begin{align*} \tau &= (R_1 + R_2) \cdot C \\ \tau &= 180 ~\Omega \cdot 40 ~nF \end{align*} |
</ | </ | ||
- | <button size=" | + | <button size=" |
- | 2. What is the value of the voltage $u_C(t)$ drop over the capacitor $C$ at $t=10 µs$? | + | 2. What is the value of the voltage $u_C(t)$ drop over the capacitor $C$ at $t=10 ~\mu s$? |
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- | \begin{align*} U_C(t) = U \cdot (1 - e^{-t/ | + | \begin{align*} |
+ | U_C(t) = U \cdot (1 - e^{-t/ | ||
+ | U_C(t) = 10 ~V \cdot (1 - e^{-10 | ||
+ | \end{align*} | ||
</ | </ | ||
- | <button size=" | + | <button size=" |
+ | |||
+ | \begin{align*} U_C(t) = 7.506 ~V \rightarrow | ||
3. What is the value of the energy, when the capacitor is fully charged? | 3. What is the value of the energy, when the capacitor is fully charged? | ||
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- | \begin{align*} W_C &= \frac{1}{2}CU^2 \\ &= \frac{1}{2} \cdot 40nF \cdot (10V)^2 \end{align*} | + | \begin{align*} |
+ | W_C &= \frac{1}{2} | ||
+ | | ||
+ | \end{align*} | ||
</ | </ | ||
- | <button size=" | + | <button size=" |
+ | \begin{align*} W_C = 2 ~\mu J \end{align*} \\ | ||
+ | </ | ||
4. Determine the new time constant when the switch $S_1$ will be opened and the switch $S_3$ will be closed simultaneously. | 4. Determine the new time constant when the switch $S_1$ will be opened and the switch $S_3$ will be closed simultaneously. | ||
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- | The capacitor $C$ discharges by the series connected resistors $R_2$ und $R_3$. \begin{align*} \tau &= (R_2 + R_3) \cdot C \\ \tau &= 130 \Omega \cdot 40 nF \end{align*} | + | The capacitor $C$ discharges by the series connected resistors $R_2$ und $R_3$. |
+ | \begin{align*} | ||
+ | \tau &= (R_2 + R_3) \cdot C \\ | ||
+ | &= 130 ~\Omega \cdot 40 ~nF | ||
+ | \end{align*} | ||
</ | </ | ||
- | <button size=" | + | <button size=" |
- | 5. When the capacitor is empty all switches will be opened. The switch $S_4$ will be closed at $t= 0$. \\ What is the voltage $u_C$ at the capacitor C after $t = 1μs$? | + | 5. When the capacitor is empty all switches will be opened. The switch $S_4$ will be closed at $t= 0$. \\ What is the voltage $u_C$ at the capacitor C after $t = 1 ~\mu s$? |
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- | The voltage $U_C$ is in general: $U_C = \frac{Q}{C}$. In this case the constant current I results in $Q = \int I dt = I \cdot t$ \begin{align*} U_C(t) &= \frac{Q}{C} \\ U_C(t) &= \frac{I \cdot t}{C} \\ U_C(1μs) &= \frac{4mA \cdot 1μs}{40nF} = \frac{4 \cdot 10^{-3}A \cdot 1\cdot 10^{-6}s}{40\cdot 10^{-9}F} \\ \end{align*} | + | The voltage $U_C$ is in general: $U_C = \frac{Q}{C}$. In this case the constant current I results in $Q = \int I dt = I \cdot t$ |
+ | \begin{align*} | ||
+ | U_C(t) | ||
+ | U_C(1μs) &= \frac{4~mA \cdot 1~\mu s}{40~nF} = \frac{4 \cdot 10^{-3}~A \cdot 1\cdot 10^{-6}~s}{40\cdot 10^{-9}~F} \\ | ||
+ | \end{align*} | ||
</ | </ | ||
- | <button size=" | + | <button size=" |
+ | \begin{align*} | ||
+ | U_C(1~\mu s) & | ||
+ | \end{align*} \\ | ||
+ | </ | ||
</ | </ |