Unterschiede

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--- electrical_engineering_and_electronics_1:block11 [2025/10/31 15:34] – mexleadmin
+++ electrical_engineering_and_electronics_1:block11 [2025/10/31 21:07] (aktuell) – mexleadmin
@@ Zeile 122: / Zeile 122: @@
   - The internal measurable electric field is compensated
 To have an uncompensated field in the following the **electric displacement flux density $\vec{D}$** is introduced.
 The electric displacement flux density is only focusing on the __cause__ of the electric fields.
-As we have seen, its effect can differ since the space can also "hinder" the electric field in an effect.
+As we have seen, its effect can differ since the space can also "hinder" the electric field in an effect. \\
 The electric displacement flux density is only related to the causing charges $Q$. Thie relationship is shown in the following.
@@ Zeile 144: / Zeile 144: @@
 </imgcaption>
 {{drawio>comparisonSwamp.svg}}
+</WRAP>
+==== Dielectric Constant (Permittivity) ====
+Dielectric materials reduce the electric field inside them. How much die field is reduced is given by a material dependent constant the **dielectric constant** or **permittivity** $\varepsilon_r$. It is unitless and a ratio related to the unhindered field in vacuum.
+\begin{align*}
+{{D}\over{E}} = \varepsilon = \varepsilon_{ \rm r} \cdot \varepsilon_0 \\
+\boxed{D = \varepsilon_{ \rm r} \cdot \varepsilon_0 \cdot E}
+\end{align*}
+Some values of the relative permittivity $\varepsilon_{ \rm r}$ for dielectrics are given in <tabref tab01>.
+<WRAP 30em>
+<tabcaption tab01| relative permittivity>
+^ material               ^ relative permittivity \\ $\varepsilon_{ \rm r}$ for low frequencies ^
+| air                    | $\rm 1.0006$  |
+| paper                  | $\rm 2$       |
+| PE, PP                 | $\rm 2.3$     |
+| PS                     | $\rm 2.5$     |
+| hard paper             | $\rm 5$       |
+| glass                  | $\rm 6...8$   |
+| water ($20~°{ \rm C}$) | $\rm 80$      |
+</tabcaption>
 </WRAP>