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--- eeng:topics:diodes:start [2022/12/08 07:30] – rolf
+++ eeng:topics:diodes:start [2023/12/13 17:11] (current) – rolf
@@ Line 3: / Line 3: @@
 ====== Diodes ======
-A diode is semiconductor device consisting of a **PN-junction**.
+A [[https://en.wikipedia.org/wiki/Diode|diode]] is semiconductor device consisting of a **PN-junction**. It circuits it works like a current valve in which the current is only flowing if the external diode voltage is in forward direction, aka forward (voltage) bias. In the reverse bias mode the diode blocks and (almost) no current can flow.
+The diode current dependance on diode voltage can be described in the (simplifying) [[https://en.wikipedia.org/wiki/Shockley_diode_equation|Shockley diode equation]] (not describing the diode breakdown):
+$
+I_D(V_D) = I_S (e^{V_D/(n V_T)} -1)
+$
+$n$ is the ideality factor.
+$
+V_T = kT/q
+$
+$T$: PN junction temperature, $q$: elementary charge, $k$: Boltzmann constant.
+| {{https://upload.wikimedia.org/wikipedia/commons/thumb/2/2a/Diode_current_wiki.png/1004px-Diode_current_wiki.png?500&direct}} |
+| Fig.: I–V (current vs. voltage) characteristics of a p–n junction diode ([[https://en.wikipedia.org/wiki/Diode#/media/File:Diode_current_wiki.png|Wikipedia]]) |
 ===== Intro to semiconductors | Class 12 (India) | Physics | Khan Academy =====