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| Beide Seiten der vorigen Revision Vorhergehende Überarbeitung Nächste Überarbeitung | Vorhergehende Überarbeitung | ||
| electrical_engineering_and_electronics_1:block17 [2025/12/02 02:00] – [Materials] mexleadmin | electrical_engineering_and_electronics_1:block17 [2025/12/06 13:45] (aktuell) – mexleadmin | ||
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| Zeile 14: | Zeile 14: | ||
| For checking your understanding please do the following exercises: | For checking your understanding please do the following exercises: | ||
| - | * ... | + | * Exercise E2 Toroidal Coil |
| + | * Task 3.2.1 Magnetic Field Strength around a horizontal straight Conductor | ||
| + | * Task 3.3.2 Electron in Plate Capacitor with magnetic Field | ||
| ===== 90-minute plan ===== | ===== 90-minute plan ===== | ||
| Zeile 134: | Zeile 136: | ||
| \\ \\ | \\ \\ | ||
| <WRAP group> | <WRAP group> | ||
| - | < | + | < |
| === Diamagnetic Materials === | === Diamagnetic Materials === | ||
| Zeile 164: | Zeile 166: | ||
| </ | </ | ||
| - | </ | + | </ |
| === Paramagnetic Materials === | === Paramagnetic Materials === | ||
| Zeile 192: | Zeile 194: | ||
| </ | </ | ||
| - | </ | + | </ |
| === Ferromagnetic Materials === | === Ferromagnetic Materials === | ||
| Zeile 208: | Zeile 210: | ||
| < | < | ||
| < | < | ||
| - | {{drawio> | + | {{drawio> |
| </ | </ | ||
| Zeile 219: | Zeile 221: | ||
| </ | </ | ||
| - | ==== Applications of the Lorentz Force ==== | + | ==== Applications of the Lorentz Force: Two parallel Conductors === |
| - | + | ||
| - | We want to apply the Lorentz force for two common situations. | + | |
| - | + | ||
| - | <WRAP group>< | + | |
| - | + | ||
| - | === Two parallel Conductors === | + | |
| The Lorentz force can be applied to two parallel conductors. \\ | The Lorentz force can be applied to two parallel conductors. \\ | ||
| Zeile 252: | Zeile 248: | ||
| \end{align*} | \end{align*} | ||
| - | </ | ||
| - | === Moving single Charge | ||
| - | |||
| - | The true Lorentz force is not the force on the whole conductor but the single force onto an (elementary) charge. \\ | ||
| - | To find this force the previous force onto a conductor can be used as a start. However, the formula will be investigated infinitesimally for small parts ${\rm d} \vec{l}$ of the conductor: | ||
| - | |||
| - | \begin{align*} | ||
| - | \vec{{\rm d}F}_{\rm L} = I \cdot {\rm d}\vec{l} \times \vec{B} | ||
| - | \end{align*} | ||
| - | |||
| - | The current is now substituted by $I = {\rm d}Q/{\rm d}t$, where ${\rm d}Q$ is the small charge packet in the length $\vec{{\rm d}l}$ of the conductor. | ||
| - | |||
| - | \begin{align*} | ||
| - | \vec{{\rm d}F}_{\rm L} = {{{\rm d}Q}\over{{\rm d}t}} \cdot {\rm d}\vec{l} \times \vec{B} | ||
| - | \end{align*} | ||
| - | |||
| - | Mathematically not quite correct, but in a physical way true the following rearrangement can be done: | ||
| - | |||
| - | \begin{align*} | ||
| - | \vec{{\rm d}F}_{\rm L} &= {{{\rm d}Q \cdot {\rm d}\vec{l}}\over{{\rm d}t}} \times \vec{B} \\ | ||
| - | & | ||
| - | & | ||
| - | \end{align*} | ||
| - | |||
| - | Here, the part ${{{\rm d}\vec{l}}\over{{\rm d}t}}$ represents the speed $\vec{v}$ of the small charge packet ${\rm d}Q$. | ||
| - | |||
| - | \begin{align*} | ||
| - | \vec{{\rm d}F}_{\rm L} &= {\rm d}Q \cdot \vec{v} \times \vec{B} | ||
| - | \end{align*} | ||
| - | |||
| - | The **Lorenz Force** on a finite charge packet is the integration: | ||
| - | |||
| - | \begin{align*} | ||
| - | \boxed{\vec{F}_{\rm L} = Q \cdot \vec{v} \times \vec{B}} | ||
| - | \end{align*} | ||
| - | |||
| - | |||
| - | |||
| - | <callout icon=" | ||
| - | |||
| - | * A charge $Q$ moving with a velocity $\vec{v}$ in a magnetic field $\vec{B}$ experiences a force of $\vec{F_{\rm L}}$. | ||
| - | * The direction of the force is given by the right-hand rule. | ||
| - | |||
| - | </ | ||
| - | |||
| - | </ | ||
| Zeile 390: | Zeile 340: | ||
| # | # | ||
| - | |||
| - | |||
| - | </ | ||
| - | |||
| - | <panel type=" | ||
| - | |||
| - | < | ||
| - | < | ||
| - | </ | ||
| - | {{drawio> | ||
| - | </ | ||
| - | |||
| - | Three long straight conductors are arranged in a vacuum to lie at the vertices of an equilateral triangle (see <imgref BildNr01> | ||
| - | |||
| - | 1. What is the magnetic field strength $H({\rm P})$ at the center of the equilateral triangle? | ||
| - | |||
| - | # | ||
| - | |||
| - | * The formula for a single wire can calculate the field of a single conductor. | ||
| - | * For the resulting field, the single wire fields have to be superimposed. | ||
| - | * Since it is symmetric the resulting field has to be neutral. | ||
| - | |||
| - | # | ||
| - | |||
| - | # | ||
| - | |||
| - | In general, the $H$-field of the single conductor is given as: | ||
| - | \begin{align*} | ||
| - | H &= {{I}\over{2\pi \cdot r}} \\ | ||
| - | &= {{2~\rm A}\over{2\pi \cdot 0.02 ~\rm m}} \\ | ||
| - | \end{align*} | ||
| - | |||
| - | * However, even without calculation, | ||
| - | * By the symmetry of the conductor, the angles of the $H$-field vectors are defined and evenly distributed on the revolution: | ||
| - | < | ||
| - | < | ||
| - | </ | ||
| - | {{drawio> | ||
| - | </ | ||
| - | # | ||
| - | |||
| - | # | ||
| - | \begin{align*} | ||
| - | H &= 0 ~\rm{{A}\over{m}} | ||
| - | \end{align*} | ||
| - | |||
| - | # | ||
| - | |||
| - | 2. Now, the current in one of the conductors is reversed. To which value does the magnetic field strength $H({\rm P})$ change? | ||
| - | |||
| - | # | ||
| - | |||
| - | * Now, the formula for a single wire has to be used to calculate the field of a single conductor. | ||
| - | * For the resulting field, the single wire fields again have to be superimposed. | ||
| - | * The symmetry and the result of question 1 give a strong hint about how much stronger the resulting field has to be compared to the field of the reversed one. | ||
| - | |||
| - | # | ||
| - | |||
| - | # | ||
| - | |||
| - | The $H$-field of the single reversed conductor $I_3$ is given as: | ||
| - | \begin{align*} | ||
| - | H(I_3) &= {{I}\over{2\pi \cdot r}} \\ | ||
| - | &= {{2~\rm A}\over{2\pi \cdot 0.02 ~\rm m}} \\ | ||
| - | \end{align*} | ||
| - | |||
| - | Once again, one can try to sketch the situation of the field vectors: | ||
| - | < | ||
| - | < | ||
| - | </ | ||
| - | {{drawio> | ||
| - | </ | ||
| - | |||
| - | Therefore, it is visible, that the resulting field is twice the value of $H(I_3)$: \\ | ||
| - | The vectors of $H(I_1)$ plus $H(I_2)$ had in the task 1 just the length of $H(I_3)$. | ||
| - | |||
| - | |||
| - | # | ||
| - | |||
| - | # | ||
| - | \begin{align*} | ||
| - | H &= 31.830... ~\rm{{A}\over{m}} \\ | ||
| - | \rightarrow H &= 31.8 ~\rm{{A}\over{m}} \\ | ||
| - | \end{align*} | ||
| - | |||
| - | # | ||
| - | |||
| - | |||
| - | </ | ||
| - | |||
| - | <panel type=" | ||
| - | |||
| - | < | ||
| - | < | ||
| - | </ | ||
| - | {{drawio> | ||
| - | </ | ||
| - | |||
| - | Given are the adjacent closed trajectories in the magnetic field of current-carrying conductors (see <imgref BildNr05> | ||
| - | |||
| - | In each case, the magnetic potential difference $V_{\rm m}$ along the drawn path is sought. | ||
| - | |||
| - | |||
| - | # | ||
| - | |||
| - | * The magnetic potential difference is given as the **sum of the current through the area within a closed path**. | ||
| - | * The direction of the current and the path have to be considered with the righthand rule. | ||
| - | |||
| - | # | ||
| - | |||
| - | # | ||
| - | a) $V_{\rm m,a} = - I_1 = - 2~\rm A$ \\ | ||
| - | # | ||
| - | |||
| - | # | ||
| - | b) $V_{\rm m,b} = - I_2 = - 4.5~\rm A$ \\ | ||
| - | # | ||
| - | |||
| - | # | ||
| - | c) $V_{\rm m,c} = 0 $ \\ | ||
| - | # | ||
| - | |||
| - | # | ||
| - | d) $V_{\rm m,d} = + I_1 - I_2 = 2~\rm A - 4.5~\rm A = - 2.5~\rm A$ \\ | ||
| - | # | ||
| - | |||
| - | # | ||
| - | e) $V_{\rm m,e} = + I_1 = + 2~\rm A$ \\ | ||
| - | # | ||
| - | |||
| - | # | ||
| - | f) $V_{\rm m,f} = 2 \cdot (- I_1) = - 4~\rm A$ \\ | ||
| - | # | ||
| </ | </ | ||
| Zeile 734: | Zeile 551: | ||
| ===== Embedded resources ===== | ===== Embedded resources ===== | ||
| Please have a look at the German contents (text, videos, exercises) on the page of the [[https:// | Please have a look at the German contents (text, videos, exercises) on the page of the [[https:// | ||
| + | \\ \\ \\ | ||
| + | <WRAP column half> | ||
| + | The rotating flux (density) in the stator of a motor, source/ | ||
| + | {{electrical_engineering_and_electronics_1: | ||
| + | </ | ||
| - | + | <WRAP column half> | |
| - | A living insect (" | + | A living insect (" |
| {{youtube> | {{youtube> | ||
| + | </ | ||
| \\ \\ | \\ \\ | ||
| - | Explanation of diamagnetism and paramagnetism | + | <WRAP column half> |
| - | < | + | Explanation of diamagnetism and paramagnetism |
| - | <WRAP column half>{{ youtube> | + | {{ youtube> |
| - | <WRAP column half>{{ youtube> | + | |
| </ | </ | ||
| + | <WRAP column half> | ||
| + | In Oxygen magnetic? \\ | ||
| + | {{ youtube> | ||
| + | </ | ||
| + | |||
| ~~PAGEBREAK~~ ~~CLEARFIX~~ | ~~PAGEBREAK~~ ~~CLEARFIX~~ | ||