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| electrical_engineering_and_electronics_2:block11 [2026/06/02 00:19] – mexleadmin | electrical_engineering_and_electronics_2:block11 [2026/06/10 03:08] (current) – mexleadmin | ||
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| - | TBD | ||
| - | |||
| - | - Semiconductor components \\ (approx. 4 blocks, based on previous lectures on [[circuit_design: | ||
| - | - Fundamentals (conductors, | ||
| - | - Diodes (real characteristic curve, operating point, equivalent circuit) | ||
| - | - Zener diode | ||
| - | - LED | ||
| - | - Protective circuit with diodes | ||
| - | - Rectifier circuits (single-phase rectifier, center tap circuit, bridge rectifier, smoothing capacitor) | ||
| - | - Bipolar transistor (structure, designations, | ||
| - | - Transistor as a switch (circuit, switching times and behavior) | ||
| - | - MOSFET (structure, comparison with bipolar transistor) | ||
| - | - Optional: Transistor as an amplifier | ||
| - | |||
| - | |||
| ====== Block 11 — Semiconductor Fundamentals and Diodes ====== | ====== Block 11 — Semiconductor Fundamentals and Diodes ====== | ||
| Line 33: | Line 18: | ||
| \] | \] | ||
| at a qualitative level. | at a qualitative level. | ||
| - | * calculate simple diode operating points with a series resistor. | ||
| - | * identify basic diode types such as universal diodes, Z-diodes, and LEDs. | ||
| </ | </ | ||
| Line 93: | Line 76: | ||
| ===== Core content ===== | ===== Core content ===== | ||
| - | |||
| - | < | ||
| < | < | ||
| Line 127: | Line 108: | ||
| < | < | ||
| <panel type=" | <panel type=" | ||
| - | < | + | < |
| {{drawio> | {{drawio> | ||
| </ | </ | ||
| Line 422: | Line 403: | ||
| ^ Symbol ^ Meaning ^ | ^ Symbol ^ Meaning ^ | ||
| | \(I_{\rm S}(T)\) | reverse saturation current, strongly temperature-dependent | | \(I_{\rm S}(T)\) | reverse saturation current, strongly temperature-dependent | ||
| - | | \(m\) | emission coefficient, | + | | \(m\) | emission coefficient, |
| - | | \(U_{\rm T}\) | thermal voltage | + | | \(U_{\rm T}\) | thermal voltage |
| | \(k\) | Boltzmann constant | | \(k\) | Boltzmann constant | ||
| | \(e\) | elementary charge | | \(e\) | elementary charge | ||
| Line 429: | Line 410: | ||
| </ | </ | ||
| \\ | \\ | ||
| - | At room temperature, | ||
| - | \[ | + | Often a **turn-on voltage** $U_{\rm |
| - | \begin{align*} | + | |
| - | U_{\rm | + | |
| - | \end{align*} | + | |
| - | \] | + | |
| - | + | ||
| - | Typical values | + | |
| < | < | ||
| Line 448: | Line 422: | ||
| <callout type=" | <callout type=" | ||
| - | The value \(0.7~{\rm V}\) for a silicon diode is not a physical constant. | + | * the turn-on voltage has also some alternative labeling: knee voltage, threshold voltage, diode voltage $U_{\rm D}$, forward voltage $U_{\rm F}$ |
| - | It is a useful approximation for typical currents in small signal and basic power circuits. | + | * The value \(U_{\rm TO} = 0.7~{\rm V}\) for a silicon diode is not a physical constant. |
| + | | ||
| </ | </ | ||
| Line 464: | Line 439: | ||
| ^ Model ^ Forward direction ^ Reverse direction ^ Use ^ Example ^ | ^ Model ^ Forward direction ^ Reverse direction ^ Use ^ Example ^ | ||
| - | | ideal diode | \(u_{\rm AK}=0\) | + | | ideal diode | \(u_{\rm AK}=0\) |
| - | | constant-voltage model | \(u_{\rm AK}\approx U_{\rm TO}\) | \(i_{\rm D}\approx 0\) | quick current calculations | + | | constant-voltage model | \(u_{\rm AK}\approx U_{\rm TO}\) |
| - | | piecewise-linear model | \(u_{\rm AK}\approx U_{\rm TO}+r_{\rm F}i_{\rm D}\) | \(i_{\rm D}\approx 0\) | more accurate operating point | How does the diode voltage change when the current changes? | + | | piecewise-linear model | \(u_{\rm AK}\approx U_{\rm TO}+r_{\rm F}\cdot i_{\rm D}\) | \(i_{\rm D}\approx 0\) | more accurate operating point | How does the diode voltage change when the current changes? |
| </ | </ | ||
| \\ | \\ | ||
| - | < | + | < |
| Line 509: | Line 484: | ||
| \] | \] | ||
| </ | </ | ||
| - | |||
| - | ==== Operating point with a series resistor ==== | ||
| - | |||
| - | A diode must usually be operated with a current-limiting element. | ||
| - | |||
| - | For the circuit | ||
| - | |||
| - | \[ | ||
| - | \begin{align*} | ||
| - | U_{\rm E} | ||
| - | \rightarrow R | ||
| - | \rightarrow D | ||
| - | \end{align*} | ||
| - | \] | ||
| - | |||
| - | the loop equation is | ||
| - | |||
| - | \[ | ||
| - | \begin{align*} | ||
| - | U_{\rm E} | ||
| - | = | ||
| - | U_R+U_{\rm D}. | ||
| - | \end{align*} | ||
| - | \] | ||
| - | |||
| - | With the constant-voltage model, | ||
| - | |||
| - | \[ | ||
| - | \begin{align*} | ||
| - | U_{\rm D}\approx U_{\rm TO}. | ||
| - | \end{align*} | ||
| - | \] | ||
| - | |||
| - | Therefore | ||
| - | |||
| - | \[ | ||
| - | \begin{align*} | ||
| - | I_{\rm D} | ||
| - | \approx | ||
| - | \frac{U_{\rm E}-U_{\rm TO}}{R}. | ||
| - | \end{align*} | ||
| - | \] | ||
| - | |||
| - | <callout type=" | ||
| - | Never connect a normal diode or LED directly to an ideal voltage source in forward direction. | ||
| - | The diode current must be limited. | ||
| - | </ | ||
| - | |||
| - | ==== Z-diodes and LEDs as diode types ==== | ||
| - | |||
| - | A Z-diode is operated in reverse breakdown. In its operating range, the diode voltage is approximately constant: | ||
| - | |||
| - | \[ | ||
| - | \begin{align*} | ||
| - | u_{\rm Z}\approx U_{\rm Z}. | ||
| - | \end{align*} | ||
| - | \] | ||
| - | |||
| - | The piecewise-linear model is | ||
| - | |||
| - | \[ | ||
| - | \begin{align*} | ||
| - | u_{\rm Z} | ||
| - | \approx | ||
| - | U_{\rm Z}+r_{\rm Z}i_{\rm Z}. | ||
| - | \end{align*} | ||
| - | \] | ||
| - | |||
| - | <panel type=" | ||
| - | Z-diodes are useful for voltage limitation and voltage stabilization. | ||
| - | The practical circuits are treated in [[block12|Block 12]]. | ||
| - | </ | ||
| - | |||
| - | An LED is a diode that emits light in forward direction. The required forward voltage depends on the semiconductor material and therefore on the color. | ||
| - | |||
| - | < | ||
| - | |||
| - | ^ LED color ^ Typical \(U_{\rm TO}\) ^ | ||
| - | | infrared | \(\approx 1.3~{\rm V}\) | | ||
| - | | red | \(\approx 1.6~{\rm V}\) | | ||
| - | | yellow | \(\approx 1.7~{\rm V}\) | | ||
| - | | green | \(\approx 1.8~{\rm V}\) | | ||
| - | | blue | \(\approx 3.2~{\rm V}\) | | ||
| - | |||
| - | <callout type=" | ||
| - | LEDs usually tolerate only small reverse voltages. | ||
| - | Do not operate an LED in reverse direction unless the datasheet explicitly allows it. | ||
| - | </ | ||
| - | |||
| - | ~~PAGEBREAK~~ ~~CLEARFIX~~ | ||
| ===== Exercises ===== | ===== Exercises ===== | ||
| Line 687: | Line 572: | ||
| \[ | \[ | ||
| \begin{align*} | \begin{align*} | ||
| - | U_{\rm | + | U_{\rm |
| \qquad | \qquad | ||
| R=1.0~{\rm k}\Omega. | R=1.0~{\rm k}\Omega. | ||
| Line 711: | Line 596: | ||
| U_R | U_R | ||
| = | = | ||
| - | U_{\rm | + | U_{\rm |
| = | = | ||
| 5.0~{\rm V}-0.7~{\rm V} | 5.0~{\rm V}-0.7~{\rm V} | ||
| Line 796: | Line 681: | ||
| \[ | \[ | ||
| \begin{align*} | \begin{align*} | ||
| - | U_{\rm | + | U_{\rm |
| \qquad | \qquad | ||
| R=560~\Omega. | R=560~\Omega. | ||
| Line 834: | Line 719: | ||
| \[ | \[ | ||
| \begin{align*} | \begin{align*} | ||
| - | U_{\rm | + | U_{\rm |
| = | = | ||
| RI_{\rm D} | RI_{\rm D} | ||
| Line 846: | Line 731: | ||
| \[ | \[ | ||
| \begin{align*} | \begin{align*} | ||
| - | U_{\rm | + | U_{\rm |
| = | = | ||
| RI_{\rm D} | RI_{\rm D} | ||
| Line 862: | Line 747: | ||
| I_{\rm D} | I_{\rm D} | ||
| = | = | ||
| - | \frac{U_{\rm | + | \frac{U_{\rm |
| \end{align*} | \end{align*} | ||
| \] | \] | ||
| Line 946: | Line 831: | ||
| ===== Embedded resources ===== | ===== Embedded resources ===== | ||
| - | |||
| - | <WRAP group> | ||
| - | <WRAP column half> | ||
| - | <panel type=" | ||
| - | Use this simulation to explore doping and the formation of a diode. | ||
| - | |||
| - | {{url> | ||
| - | </ | ||
| - | </ | ||
| - | |||
| - | <WRAP column half> | ||
| - | <panel type=" | ||
| - | Use this simulation to compare a resistor characteristic with the nonlinear diode characteristic. | ||
| - | |||
| - | {{url> | ||
| - | </ | ||
| - | </ | ||
| - | </ | ||
| ~~PAGEBREAK~~ ~~CLEARFIX~~ | ~~PAGEBREAK~~ ~~CLEARFIX~~ | ||