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| electrical_engineering_and_electronics_2:block11 [2026/06/02 00:50] – mexleadmin | electrical_engineering_and_electronics_2:block11 [2026/06/10 03:08] (current) – mexleadmin |
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| \] | \] |
| 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. | |
| </callout> | </callout> |
| |
| |
| ===== Core content ===== | ===== Core content ===== |
| |
| <callout> A nice introduction to the bipolar transistor can be found in [[http://eng.libretexts.org/Bookshelves/Materials_Science/Supplemental_Modules_(Materials_Science)/Materials_and_Devices/Bipolar_Junction_Transistor|libretexts]]. Some of the following passages, videos and pictures are taken from this introduction. </callout> | |
| |
| <WRAP><callout type="info" icon="true"> | <WRAP><callout type="info" icon="true"> |
| <WRAP> | <WRAP> |
| <panel type="default"> | <panel type="default"> |
| <imgcaption sep_Res|sepcific resistance for selected conductors, semiconductors, and insulators.></imgcaption> | <imgcaption sep_Res|specific resistance for selected conductors, semiconductors, and insulators.></imgcaption> |
| {{drawio>block11_specResistanceV02.svg}} | {{drawio>block11_specResistanceV02.svg}} |
| </panel> | </panel> |
| ^ 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, typically \(1\ldots 2\) | | | \(m\) | emission coefficient, typically \(1\ldots 2\), material constant | |
| | \(U_{\rm T}\) | thermal voltage ($U_{\rm T}\approx 26~{\rm mV}$ at room temperature) | | | \(U_{\rm T}\) | thermal voltage ($U_{\rm T}\approx 26~{\rm mV}$ at room temperature) | |
| | \(k\) | Boltzmann constant | | | \(k\) | Boltzmann constant | |
| {{url>https://www.falstad.com/circuit/circuitjs.html?hideSidebar=true&ctz=CQAgjA7CAMB00OgVhrAbAJiQFgggnEmPgMxokkgAcKGIS09ApgLRhgBQARuPnWNmz0MQso2gcAHiAwkw4OSGxh+JIUIyMATkwCGAGwA6AZwAmASwD2ppiYAUARobQAtgDUAlBwDmMkTKoqP1FNGBgONXAAOWVsKgB9MOxYEiQMVnxUNGwkILBYfGg0cDBxDlNgmWggjH8MQJlo2ISOACVKzRr-SGLGSgZUFHFBjmxoSgwIfghiojpUukZseOz46HjlNAh4-KxWJDR4qn3tsHiMDfiSNpA2eqqgu7yZsP7xAqGwuCRy25Ua6p-e71GpNAQtXxPAKPf4gCi9cLSFj4eQqTKFBR0DTaPRGMxWGz2ByEVyebh-NCMARCSDzSnhMaUFhUKkvMD0hZhbZzNYbdlnJAZQ75NBC3kXbbXaTYYpgGj0VENGlBACSUjh+DyVHkjPAVHUepAaukYDSARQ7I0SsNAFV1Qx5PV+mAJlRisqQHbpBArbL2AFMh64BA3OrSo60JlSrQpkpDQAfdWCK2B7UyPhxuWobCh6VbGQQHWFgsGrOJ6QYfCZERQOSOgYer1w00yHBwrCtqAegBaNyhcUY-bir3o70ow2+v37LKBQQOjH4MXB8R8s-o9KhSAzZV1zKWw-ZjEwQgXJHiPPWmwFrDiGxvh3WF1kV3JbHISnZ4EjIHIi3Vd3UcZ6C7Io41CHQDBMCxrFsYxHBIBB3C8aVKByVCghyd1DWNcAZXoJALVyfCMNtdU8HXGloCgA4u0NOAMFzEAUXoQQmJQHBaLLf8DgVTIWFYtIsVIpExmEYoWAQ4RA0NXtpBISs-EoEg01qLCs1KaBAB7gABBdVlKgDABA1AzIEzIIVyRTJnBkN5UMNMAdL0lBsFIJRnPwNTzL0iZiCUCZajMkALNuOoFIoGyhPUxDdKRdggnwdQfSY2j-GgwljAAYwAC10LRdAygAXJgtHMYwCvMDKoKYAAHJgADsLDq7wTEsOqTAAN0sfQCt0bwmAAegygBXLQdDqgqTDypqmHVWoMKAkh8BArDwNxKCCVgxwGCQ1daiEedKi3RZwgqPalBnM6DsXZoV3aM6B0qQQgj6UdUGQL4Rl1SYsWHOYf38JYz1KEReU2M80FgEQq2hmGYdYSB4nwWAZgOPYWEM8UNjPa4eGILEjLSIRyDKOTNTcnUgJyUtVXtaB5AI51+h4xskw7VHzroA5nLo+AsEY7BUhY5zFpYkiuIrKsFVrf00iWYTm3Y-x5MVziglkhWlAzZSsUIQK4AQJBHLkt1NaUjzNc8oKOCAA noborder}} | {{url>https://www.falstad.com/circuit/circuitjs.html?hideSidebar=true&ctz=CQAgjA7CAMB00OgVhrAbAJiQFgggnEmPgMxokkgAcKGIS09ApgLRhgBQARuPnWNmz0MQso2gcAHiAwkw4OSGxh+JIUIyMATkwCGAGwA6AZwAmASwD2ppiYAUARobQAtgDUAlBwDmMkTKoqP1FNGBgONXAAOWVsKgB9MOxYEiQMVnxUNGwkILBYfGg0cDBxDlNgmWggjH8MQJlo2ISOACVKzRr-SGLGSgZUFHFBjmxoSgwIfghiojpUukZseOz46HjlNAh4-KxWJDR4qn3tsHiMDfiSNpA2eqqgu7yZsP7xAqGwuCRy25Ua6p-e71GpNAQtXxPAKPf4gCi9cLSFj4eQqTKFBR0DTaPRGMxWGz2ByEVyebh-NCMARCSDzSnhMaUFhUKkvMD0hZhbZzNYbdlnJAZQ75NBC3kXbbXaTYYpgGj0VENGlBACSUjh+DyVHkjPAVHUepAaukYDSARQ7I0SsNAFV1Qx5PV+mAJlRisqQHbpBArbL2AFMh64BA3OrSo60JlSrQpkpDQAfdWCK2B7UyPhxuWobCh6VbGQQHWFgsGrOJ6QYfCZERQOSOgYer1w00yHBwrCtqAegBaNyhcUY-bir3o70ow2+v37LKBQQOjH4MXB8R8s-o9KhSAzZV1zKWw-ZjEwQgXJHiPPWmwFrDiGxvh3WF1kV3JbHISnZ4EjIHIi3Vd3UcZ6C7Io41CHQDBMCxrFsYxHBIBB3C8aVKByVCghyd1DWNcAZXoJALVyfCMNtdU8HXGloCgA4u0NOAMFzEAUXoQQmJQHBaLLf8DgVTIWFYtIsVIpExmEYoWAQ4RA0NXtpBISs-EoEg01qLCs1KaBAB7gABBdVlKgDABA1AzIEzIIVyRTJnBkN5UMNMAdL0lBsFIJRnPwNTzL0iZiCUCZajMkALNuOoFIoGyhPUxDdKRdggnwdQfSY2j-GgwljAAYwAC10LRdAygAXJgtHMYwCvMDKoKYAAHJgADsLDq7wTEsOqTAAN0sfQCt0bwmAAegygBXLQdDqgqTDypqmHVWoMKAkh8BArDwNxKCCVgxwGCQ1daiEedKi3RZwgqPalBnM6DsXZoV3aM6B0qQQgj6UdUGQL4Rl1SYsWHOYf38JYz1KEReU2M80FgEQq2hmGYdYSB4nwWAZgOPYWEM8UNjPa4eGILEjLSIRyDKOTNTcnUgJyUtVXtaB5AI51+h4xskw7VHzroA5nLo+AsEY7BUhY5zFpYkiuIrKsFVrf00iWYTm3Y-x5MVziglkhWlAzZSsUIQK4AQJBHLkt1NaUjzNc8oKOCAA noborder}} |
| </WRAP> | </WRAP> |
| | |
| | ==== Practical diode models for circuit calculation ==== |
| | |
| | For hand calculations we usually do not use the full exponential equation, because it is often too complex for a quick solution. \\ |
| | Instead the following is often used: |
| | |
| | <tabcaption tab_diode_models|Diode models for circuit calculations> |
| | |
| | ^ Model ^ Forward direction ^ Reverse direction ^ Use ^ Example ^ |
| | | ideal diode | \(u_{\rm AK}=0\) | \(i_{\rm D}=0\) | switching logic, first estimate | Is the rectifier path conducting? | |
| | | constant-voltage model | \(u_{\rm AK}\approx U_{\rm TO}\) | \(i_{\rm D}\approx 0\) | quick current calculations | Which current flows through an LED and its series resistor? | |
| | | 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? | |
| | </tabcaption> |
| | \\ |
| | <WRAP>{{url>https://www.falstad.com/circuit/circuitjs.html?running=false&ctz=DwYwlgTgBAZgvAIgIwHYFQC4GdEAYB0uRuArOmCIkvgCwDMAnEkwGy4MlI0MAcDd6EACNEJXOgAOIhGPQA3CFXQBbbKICmAWiRIEAPgBQUKMCFQAHohYkWUJACYeUDrbpt08BOID0h48HMLKx4nHVwoFH47JAFYRBp0LDBEewTMdUQIdQBDABsoABMwAHsC9QRfIxMAcyCEFhCoOntwhqc6Nw88Cr8TArq2uwZ7KEHm8TiEexViqgA5GiIEyv8AJQHG5hHBpHdJiYB3T1iYRRkJ5WzzOTx8Hh6q4ABlEGKJdTqUXBo7NmcaH4dFhdLz6Kr+YpQdQAO3iiQkVjSnnM9EkiG0YOMWJMEigN1BUCwlGQhC4Dm+PFwSB49hIPE6K2xOLxiFiRNuu3stOGKAa9mGMToaEZ-m8xV6wG8Lze6glgUsCGGTnsKBGDEWUBVZEmaSSVHu6UQAFUHv55Yh6eFdk56SQ7ChdDrEslkAaMBkEABJU0mc0IHgoFCa1XOLjB7WeXUu6nod23FAANR9wDkdSQRGVIfTuGVqRBh08Fyu+IIwol0AV2dCwzsGc1ef26DOukZATTdbC0Qa0ROcMJLobcYQYDKeTAAC91P0iqVyq3apW6+Nazmmp1G62CsooNDlIgYAcChA3nACFT8+QcMgtGgoBArxNYV5CA2hCXk-1F6uVSMq00WiC0xQMoswIAeR4nmeLYSusX7Vr+HZ7IW6BHKyHhnLIwHFrc9yttK7zthquxWo44RAhevQQlCT5cPCVC4A2yI0EBCIIBilFYsAuLvoSxIEAw6osDQQmqjwzAkCgHQ+tiXEsggbJ8fgSAkEw9D0DYnAxKgAgiiYYoSlKrzvBKZgKrwv6OHY-LtEh3Stn6DgsLY9jdg4KCZo6kbOvqsYeia9lprsthBdEDq-AwIJRj5hpesmDn2GGKokZwwa9ggUWur58ZJpUkrgBAhhAA noborder}} \\ </WRAP> |
| | |
| | |
| | The differential forward resistance is |
| | |
| | \[ |
| | \begin{align*} |
| | r_{\rm F} |
| | = |
| | \frac{\Delta U_{\rm F}}{\Delta I_{\rm F}}. |
| | \end{align*} |
| | \] |
| | |
| | For large forward voltages compared with \(U_{\rm T}\), the diode equation leads approximately to |
| | |
| | \[ |
| | \begin{align*} |
| | r_{\rm D} |
| | = |
| | \frac{{\rm d}u_{\rm D}}{{\rm d}i_{\rm D}} |
| | \approx |
| | \frac{mU_{\rm T}}{I_{\rm D}}. |
| | \end{align*} |
| | \] |
| | |
| | <callout type="info" icon="true"> |
| | **Unit check** |
| | |
| | \[ |
| | \begin{align*} |
| | [r_{\rm D}] |
| | = |
| | \frac{[U_{\rm T}]}{[I_{\rm D}]} |
| | = |
| | \frac{{\rm V}}{{\rm A}} |
| | = |
| | \Omega. |
| | \end{align*} |
| | \] |
| | </callout> |
| |
| ===== Exercises ===== | ===== Exercises ===== |
| \[ | \[ |
| \begin{align*} | \begin{align*} |
| U_{\rm E}=5.0~{\rm V}, | U_{\rm I}=5.0~{\rm V}, |
| \qquad | \qquad |
| R=1.0~{\rm k}\Omega. | R=1.0~{\rm k}\Omega. |
| U_R | U_R |
| = | = |
| U_{\rm E}-U_{\rm D} | U_{\rm I}-U_{\rm D} |
| = | = |
| 5.0~{\rm V}-0.7~{\rm V} | 5.0~{\rm V}-0.7~{\rm V} |
| \[ | \[ |
| \begin{align*} | \begin{align*} |
| U_{\rm E}=12~{\rm V}, | U_{\rm I}=12~{\rm V}, |
| \qquad | \qquad |
| R=560~\Omega. | R=560~\Omega. |
| \[ | \[ |
| \begin{align*} | \begin{align*} |
| U_{\rm E} | U_{\rm I} |
| = | = |
| RI_{\rm D} | RI_{\rm D} |
| \[ | \[ |
| \begin{align*} | \begin{align*} |
| U_{\rm E} | U_{\rm I} |
| = | = |
| RI_{\rm D} | RI_{\rm D} |
| I_{\rm D} | I_{\rm D} |
| = | = |
| \frac{U_{\rm E}-U_{\rm TO}}{R+r_{\rm F}}. | \frac{U_{\rm I}-U_{\rm TO}}{R+r_{\rm F}}. |
| \end{align*} | \end{align*} |
| \] | \] |
| |
| ===== Embedded resources ===== | ===== Embedded resources ===== |
| |
| <WRAP group> | |
| <WRAP column half> | |
| <panel type="info" title="PhET: Semiconductors"> | |
| Use this simulation to explore doping and the formation of a diode. | |
| |
| {{url>https://phet.colorado.edu/en/simulations/semiconductor 700,500 noborder}} | |
| </panel> | |
| </WRAP> | |
| |
| <WRAP column half> | |
| <panel type="info" title="Falstad: Diode I/V curve"> | |
| Use this simulation to compare a resistor characteristic with the nonlinear diode characteristic. | |
| |
| {{url>https://www.falstad.com/circuit/e-diodecurve.html 700,500 noborder}} | |
| </panel> | |
| </WRAP> | |
| </WRAP> | |
| |
| ~~PAGEBREAK~~ ~~CLEARFIX~~ | ~~PAGEBREAK~~ ~~CLEARFIX~~ |