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| electrical_engineering_and_electronics_1:the_electrostatic_field [2025/09/19 12:32] – ↷ Links angepasst, weil Seiten im Wiki verschoben wurden mexleadmin | electrical_engineering_and_electronics_1:the_electrostatic_field [2025/09/19 16:04] (current) – [Bearbeiten - Panel] mexleadmin | ||
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| - | ====== | + | ====== |
| < | < | ||
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| </ | </ | ||
| - | We had already considered the charge as the central quantity of electricity in the first chapter | + | We had already considered the charge as the central quantity of electricity in the first chapter and recognized it as a multiple of the elementary charge. There was already a mutual force action ([[electrical_engineering_1: |
| First, we shall define certain terms: | First, we shall define certain terms: | ||
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| ~~PAGEBREAK~~ ~~CLEARFIX~~ | ~~PAGEBREAK~~ ~~CLEARFIX~~ | ||
| - | ===== 1.1 Electric Field and Field Lines ===== | + | ===== 5.1 Electric Field and Field Lines ===== |
| < | < | ||
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| ==== The Electric Field ==== | ==== The Electric Field ==== | ||
| - | To determine the electric field, a measurement of its magnitude and direction is now required. The Coulomb force between two charges $Q_1$ and $Q_2$ is known from the first chapter | + | To determine the electric field, a measurement of its magnitude and direction is now required. The Coulomb force between two charges $Q_1$ and $Q_2$ is known from the first chapter |
| \begin{align*} | \begin{align*} | ||
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| ==== Tasks ==== | ==== Tasks ==== | ||
| - | <panel type=" | + | <panel type=" |
| {{youtube> | {{youtube> | ||
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| </ | </ | ||
| - | <panel type=" | + | <panel type=" |
| Sketch the field line plot for the charge configurations given in <imgref ImgNr04> | Sketch the field line plot for the charge configurations given in <imgref ImgNr04> | ||
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| - | ===== 1.2 Electric Charge and Coulomb Force (reloaded) ===== | + | ===== 5.2 Electric Charge and Coulomb Force (reloaded) ===== |
| < | < | ||
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| </ | </ | ||
| - | The electric charge and Coulomb force have already been described | + | The electric charge and Coulomb force have already been described |
| ==== Direction of the Coulomb force and Superposition ==== | ==== Direction of the Coulomb force and Superposition ==== | ||
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| ==== Tasks ==== | ==== Tasks ==== | ||
| - | {{page> | + | {{page> |
| - | {{page> | + | {{page> |
| - | {{page> | + | {{page> |
| - | <panel type=" | + | <panel type=" |
| {{youtube> | {{youtube> | ||
| </ | </ | ||
| - | {{page> | + | {{page> |
| - | {{page> | + | {{page> |
| - | {{page> | + | {{page> |
| - | =====1.3 Work and Potential ===== | + | =====5.3 Work and Potential ===== |
| < | < | ||
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| \end{align*} | \end{align*} | ||
| - | This concept has already been applied as Kirchhoff' | + | This concept has already been applied as Kirchhoff' |
| <callout icon=" | <callout icon=" | ||
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| </ | </ | ||
| - | =====1.4 Conductors in the Electrostatic Field ===== | + | =====5.4 Conductors in the Electrostatic Field ===== |
| < | < | ||
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| Application of electrostatic induction: Protective bag against electrostatic charge/ | Application of electrostatic induction: Protective bag against electrostatic charge/ | ||
| - | <panel type=" | + | <panel type=" |
| < | < | ||
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| </ | </ | ||
| - | {{page> | + | {{page> |
| - | {{page> | + | {{page> |
| - | {{page> | + | {{page> |
| - | <wrap anchor #exercise_1_4_5 | + | <wrap anchor #exercise_5_4_5 |
| - | <panel type=" | + | <panel type=" |
| Given is the two-dimensional component shown in <imgref ImgNr148> | Given is the two-dimensional component shown in <imgref ImgNr148> | ||
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| </ | </ | ||
| - | =====1.5 The Electric Displacement Field and Gauss' | + | =====5.5 The Electric Displacement Field and Gauss' |
| < | < | ||
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| ==== tasks==== | ==== tasks==== | ||
| - | <panel type=" | + | <panel type=" |
| A plate capacitor with a distance of $d = 2 ~{ \rm cm}$ between the plates and with air as dielectric ($\varepsilon_{ \rm r}=1$) gets charged up to $U = 5~{ \rm kV}$. | A plate capacitor with a distance of $d = 2 ~{ \rm cm}$ between the plates and with air as dielectric ($\varepsilon_{ \rm r}=1$) gets charged up to $U = 5~{ \rm kV}$. | ||
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| Calculate the amount of the displaced charges in the thin metal foil. | Calculate the amount of the displaced charges in the thin metal foil. | ||
| - | <button size=" | + | <button size=" |
| * What is the strength of the electric field $E$ in the capacitor? | * What is the strength of the electric field $E$ in the capacitor? | ||
| * Calculate the displacement flux density $D$ | * Calculate the displacement flux density $D$ | ||
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| </ | </ | ||
| - | <button size=" | + | <button size=" |
| $Q = 10 ~{ \rm nC}$ | $Q = 10 ~{ \rm nC}$ | ||
| </ | </ | ||
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| - | <panel type=" | + | <panel type=" |
| An ideal plate capacitor with a distance of $d_0 = 7 ~{ \rm mm}$ between the plates gets charged up to $U_0 = 190~{ \rm V}$ by an external source. | An ideal plate capacitor with a distance of $d_0 = 7 ~{ \rm mm}$ between the plates gets charged up to $U_0 = 190~{ \rm V}$ by an external source. | ||
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| - How does the situation change (electric field/ | - How does the situation change (electric field/ | ||
| - | <button size=" | + | <button size=" |
| * Consider the displacement flux through a surface around a plate | * Consider the displacement flux through a surface around a plate | ||
| </ | </ | ||
| - | <button size=" | + | <button size=" |
| - $U_1 = 1.9~{ \rm kV}$, $E_1 = 27~{ \rm kV/ | - $U_1 = 1.9~{ \rm kV}$, $E_1 = 27~{ \rm kV/ | ||
| - $U_1 = 190~{ \rm V}$, $E_1 = 2.7~{ \rm kV/ | - $U_1 = 190~{ \rm V}$, $E_1 = 2.7~{ \rm kV/ | ||
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| - | <panel type=" | + | <panel type=" |
| An ideal plate capacitor with a distance of $d_0 = 6 ~{ \rm mm}$ between the plates and with air as dielectric ($\varepsilon_0=1$) is charged to a voltage of $U_0 = 5~{ \rm kV}$. | An ideal plate capacitor with a distance of $d_0 = 6 ~{ \rm mm}$ between the plates and with air as dielectric ($\varepsilon_0=1$) is charged to a voltage of $U_0 = 5~{ \rm kV}$. | ||
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| - | <panel type=" | + | <panel type=" |
| Two concentric spherical conducting plates set up a spherical capacitor. | Two concentric spherical conducting plates set up a spherical capacitor. | ||
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| - | <panel type=" | + | <panel type=" |
| {{youtube> | {{youtube> | ||
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| ~~PAGEBREAK~~ ~~CLEARFIX~~ | ~~PAGEBREAK~~ ~~CLEARFIX~~ | ||
| - | =====1.6 Non-Conductors in electrostatic Field ===== | + | =====5.6 Non-Conductors in electrostatic Field ===== |
| < | < | ||
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| ==== tasks==== | ==== tasks==== | ||
| - | <panel type=" | + | <panel type=" |
| Consider what would have happened if the plates had not been detached from the voltage source in the above thought experiment (<imgref ImgNr13> | Consider what would have happened if the plates had not been detached from the voltage source in the above thought experiment (<imgref ImgNr13> | ||
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| </ | </ | ||
| - | =====1.7 Capacitors ===== | + | =====5.7 Capacitors ===== |
| < | < | ||
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| - | =====1.8 Circuits with Capacitors ===== | + | =====5.8 Circuits with Capacitors ===== |
| < | < | ||
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| In the simulation below, besides the parallel connected capacitors $C_1$, $C_2$, | In the simulation below, besides the parallel connected capacitors $C_1$, $C_2$, | ||
| * The switch $S$ allows the voltage source to charge the capacitors. | * The switch $S$ allows the voltage source to charge the capacitors. | ||
| - | * The resistor $R$ is necessary because the simulation cannot represent instantaneous charging. The resistor limits the charging current to a maximum value. \\ This leads to the DC circuit transients, explained in the [[electrical_engineering_1: | + | * The resistor $R$ is necessary because the simulation cannot represent instantaneous charging. The resistor limits the charging current to a maximum value. |
| * The capacitors can be discharged again via the lamp. | * The capacitors can be discharged again via the lamp. | ||
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| ====Tasks==== | ====Tasks==== | ||
| - | <panel type=" | + | <panel type=" |
| See https:// | See https:// | ||
| </ | </ | ||
| - | =====1.9 Configurations of multiple Dielectrics ===== | + | ===== 5.9 Configurations of multiple Dielectrics |
| < | < | ||
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| \begin{align*} | \begin{align*} | ||
| U = \int \limits_{\rm path \, inside \\ the \, capacitor} \! \! \vec{E} \cdot {\rm d} \vec{s} = E_1 \cdot d_1 + E_2 \cdot d_2 + E_3 \cdot d_3 | U = \int \limits_{\rm path \, inside \\ the \, capacitor} \! \! \vec{E} \cdot {\rm d} \vec{s} = E_1 \cdot d_1 + E_2 \cdot d_2 + E_3 \cdot d_3 | ||
| - | \tag{1.9.1} | + | \tag{5.9.1} |
| \end{align*} | \end{align*} | ||
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| \begin{align*} | \begin{align*} | ||
| \boxed{ | \boxed{ | ||
| - | \tag{1.9.2} | + | \tag{5.9.2} |
| \end{align*} | \end{align*} | ||
| - | Using $(1.9.1)$ and $(1.9.2)$ we can also derive the following relationship: | + | Using $(5.9.1)$ and $(5.9.2)$ we can also derive the following relationship: |
| \begin{align*} | \begin{align*} | ||
| E_2 = & {{\varepsilon_{ \rm r1}}\over{\varepsilon_{ \rm r2}}}\cdot E_1 , \quad E_3 = {{\varepsilon_{ \rm r1}}\over{\varepsilon_{ \rm r3}}}\cdot E_1 \\ | E_2 = & {{\varepsilon_{ \rm r1}}\over{\varepsilon_{ \rm r2}}}\cdot E_1 , \quad E_3 = {{\varepsilon_{ \rm r1}}\over{\varepsilon_{ \rm r3}}}\cdot E_1 \\ | ||
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| \end{align*} | \end{align*} | ||
| - | The formula obtained represents the law of refraction of the field line at interfaces. There is also a hint that for electromagnetic waves (like visible light) the refractive index might depend on the dielectric constant. This is the case. However, in the calculation presented here, electrostatic fields were assumed. In the case of electromagnetic waves, the distribution of energy between the two fields must be taken into account. This is not considered in detail in this course but is explained shortly in task 1.9.1. | + | The formula obtained represents the law of refraction of the field line at interfaces. There is also a hint that for electromagnetic waves (like visible light) the refractive index might depend on the dielectric constant. This is the case. However, in the calculation presented here, electrostatic fields were assumed. In the case of electromagnetic waves, the distribution of energy between the two fields must be taken into account. This is not considered in detail in this course but is explained shortly in task 5.9.1. |
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| ====Tasks==== | ====Tasks==== | ||
| - | <panel type=" | + | <panel type=" |
| {{youtube> | {{youtube> | ||
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| </ | </ | ||
| - | <panel type=" | + | <panel type=" |
| {{youtube> | {{youtube> | ||
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| </ | </ | ||
| - | <panel type=" | + | <panel type=" |
| {{youtube> | {{youtube> | ||
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| </ | </ | ||
| - | <panel type=" | + | <panel type=" |
| {{youtube> | {{youtube> | ||
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| </ | </ | ||
| - | <panel type=" | + | <panel type=" |
| < | < | ||
| Line 1658: | Line 1658: | ||
| </ | </ | ||
| - | {{page> | + | {{page> |
| - | =====1.10 Summary ===== | + | =====5.10 Summary ===== |
| < | < | ||