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| electrical_engineering_and_electronics_1:uebung_3.5.2 [2025/09/19 14:13] – angelegt mexleadmin | electrical_engineering_and_electronics_1:uebung_3.5.2 [2025/12/13 23:12] (aktuell) – [Bearbeiten - Panel] mexleadmin |
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| <WRAP pagebreak></WRAP> <panel type="info" title="Exercise 3.5.2. Variations of the non-inverting amplifier"> <WRAP group><WRAP column 2%>{{fa>pencil?32}}</WRAP><WRAP column 92%> | <WRAP pagebreak></WRAP> |
| | <panel type="info" title="Exercise 3.5.2. Variations of the non-inverting amplifier"> <WRAP group><WRAP column 2%>{{fa>pencil?32}}</WRAP><WRAP column 92%> |
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| Below you will find circuits with an ideal operational amplifier, which are similar to the non-inverting amplifier and whose voltage gain $A_V$ must be determined. | Below you will find circuits with an ideal operational amplifier, which are similar to the non-inverting amplifier and whose voltage gain $A_V$ must be determined. |
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| **__Important__**: As always in your studies, you should try to generalize the knowledge gained from the task. | **__Important__**: As always in your studies, you should try to generalize the knowledge gained from the task. |
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| <WRAP onlyprint> **Tipps** | |
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| * How big is the current flow into the inverting and non-inverting input of an ideal operational amplifier? So what voltage drop would there be across a resistor whose one connection only leads to one input of the operational amplifier ($R_3$)? | |
| * The operational amplifier always tries to output as much current at the output that the required minimum voltage $U_\rm D$ results between the inverting and non-inverting input. How high can $U_\rm D$ be assumed? Can this voltage also be built up via a resistor ($R_4$)? | |
| * Can different resistors (e.g. because they are between the same nodes) be combined? | |
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| <WRAP right><panel type="default"> Abb. 1 \\ {{drawio>pic3_5_2_Aufgabe1.svg}} </panel></WRAP> \\ \\ \\ \\ \\ \\ \\ \\ <WRAP noprint> | <WRAP right><panel type="default"> Abb. 1 \\ {{drawio>pic3_5_2_Aufgabe1.svg}} </panel></WRAP> |
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| ++++ Hints| | ++++ Hints| |
| ++++ | ++++ |
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| </WRAP> | |
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| </WRAP><WRAP half column> | </WRAP><WRAP half column> |
| <WRAP right><panel type="default"> Abb. 2 \\ {{drawio>pic3_5_2_Aufgabe2.svg}} </panel></WRAP> | <WRAP right><panel type="default"> Abb. 2 \\ {{drawio>pic3_5_2_Aufgabe2.svg}} </panel></WRAP> |
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| \\ \\ \\ \\ \\ \\ \\ \\ <WRAP noprint> | |
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| ++++ Hints| | ++++ Hints| |
| ++++ | ++++ |
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| </WRAP></WRAP></WRAP> | </WRAP> |
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| <WRAP onlyprint> \\ \\ \\ \\ \\ \\ \\ \\ </WRAP> <WRAP group><WRAP half column> | |
| | <button size="xs" type="link" collapse="sol3521">{{icon>eye}} Solution for (1) + (2)</button><collapse id="sol3521" collapsed="true"> |
| | Fig. 1 |
| | * Between the inverting and non-inverting input, only $U_D \rightarrow 0$ is present. As long as $R_4 > 0$, this small voltage can exist there. Therefore, $R_4$ can be replaced by an open circuit. |
| | * Since no current flows through $R_3$, there is no voltage difference across $R_3$. Thus, $R_3$ can be replaced by a short circuit. |
| | * This results in a non-inverting amplifier with $A_V = 3/2$ |
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| | <WRAP right>{{url>https://www.falstad.com/circuit/circuitjs.html?ctz=CQAgjCAMB0l3BWcMBMcUHYMGZIA4UA2ATmIxAUgpABZsAoAQxExVr1rnZGPCQFowSMPHhRopUhnhgwkhGxiTieSokkZCEEaPoAnFihohsbFEZB4qVHZH2HjphyH5Ob8ezRodvtX7MVkOE9-MDYvDjBNKBYPAHM-SOiI2I5regB3RPAw5wCoTLzc82MrAqzWEEJjSrK7Cow2MpLLdIa2Jxa3QpouXxTfeudXNjk2EYKAJXBicacwLxc3GN7wGOtoBHpsQh9+jgUfNIKgA 500,400 noborder}} |
| | </WRAP> |
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| | ~~PAGEBREAK~~ ~~CLEARFIX~~ |
| | Fig. 2 |
| | * No current flows through $R_3$, since no current can flow into the op-amp. Therefore, there is no voltage difference across $R_3$, and $R_3$ can be replaced by a short circuit. |
| | * $R_4$ and $R_2$ are in parallel and yield $R_g = \frac{2}{3} R_1$ |
| | * The gain thus becomes $A_V = \frac{R_g + R_1}{R_g} = 2.5$ |
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| | <WRAP right>{{url>https://www.falstad.com/circuit/circuitjs.html?ctz=CQAgjCAMB0l3BWcMBMcUHYMGZIA4UA2ATmIxAUgpABZsAoAQxExVr1rnZGPCQFowSMPHhRopUhkpxCKGsTx1wyUfQBOLeeDBsU2sISpURcDVpo692mhxPxzNW9yccwuqKsiPn7tq-AMQk80MwBzWl8gyI40Oyh6AHcYqwtU72TWbizCSwyWDH9YmzskgrZsa0tKhOSaLmcA528AJTSasGia404VHpgEemxCDiaOBBRR+PyAzuD9SznatKWF8CMEoA 500,400 noborder}} |
| | </WRAP> |
| | </collapse> |
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| | </WRAP> |
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| | <WRAP group><WRAP half column> |
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| <WRAP right><panel type="default"> Abb. 3 \\ {{drawio>pic3_5_2_Aufgabe3.svg}} </panel></WRAP> </WRAP><WRAP half column> | <WRAP right><panel type="default"> Abb. 3 \\ {{drawio>pic3_5_2_Aufgabe3.svg}} </panel></WRAP> </WRAP><WRAP half column> |
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| <WRAP right><panel type="default"> Abb. 4 \\ {{drawio>pic3_5_2_Aufgabe4.svg}} </panel></WRAP> </WRAP></WRAP> | <WRAP right><panel type="default"> Abb. 4 \\ {{drawio>pic3_5_2_Aufgabe4.svg}} </panel></WRAP> </WRAP></WRAP> |
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| | <button size="xs" type="link" collapse="sol3522">{{icon>eye}} Solution for (3) + (4)</button><collapse id="sol3522" collapsed="true"> |
| | Fig. 3 |
| | * $R_3$ and $R_4$ form an unloaded voltage divider. |
| | * Thus, the input voltage is halved. |
| | * This results in a non-inverting amplifier with $A_V = \frac{R_2 + R_1}{R_2} = 0.75$ |
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| | <WRAP right>{{url>https://www.falstad.com/circuit/circuitjs.html?ctz=CQAgjCAMB0l3BWcMBMcUHYMGZIA4UA2ATmIxAUgpABZsAoAQxExVr1rnZGPCQFowSMPHhRopUhnhgwkhGxiTieSokkZCEEaPoAnFihohsbFEZB4qVHZH2HjphyH5Ob8ezRodvtX7MVkOE9-MDYvDjBNKBYPAHM-SOiI2I5regB3RPAw5wCoTLzc82MrAqzWEEJjSrK7Cow2MpLLdIa2Jxa3QpouXxTfeudXNjk2EYKAJXBicacwLxc3GN7wGOtoBHpsQh9+jgUfNIKgA 500,400 noborder}} |
| | </WRAP> |
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| | ~~PAGEBREAK~~ ~~CLEARFIX~~ |
| | Fig. 4 |
| | * No current flows through $R_3$, since no current can flow into the op-amp. Therefore, there is no voltage difference across $R_3$, and $R_3$ can be replaced by a short circuit. |
| | * Since the input voltage comes from a low-impedance voltage source, $R_4$ is negligible compared to the internal resistance of the source. Therefore, $R_4$ can be replaced by an open circuit. |
| | * The overall gain thus becomes $A_V = 3/2$ |
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| | <WRAP right>{{url>https://www.falstad.com/circuit/circuitjs.html?ctz=CQAgjCAMB0l3BWcMBMcUHYMGZIA4UA2ATmIxAUgpABZsAoAQxExVr1rnZGPCQFowSMPHhRopUnkroUNUoULhko+gCcWckNjYotYQlSoi46zTW26MbHVBWQzNGh2e1XYMG2PxH7z244wDCUqNFMAcwDwYKi0DiN6AHcojys2VKgklmsQQgtWcH8HZL0LfltSy0zkmi5XJxd4+gAlcxBy9JiOuypa5SNxBHpsQhd6jgQURp6shuilSqCQrMWYxcNMoA 500,400 noborder}} |
| | </WRAP></collapse> |
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| <WRAP pagebreak></WRAP> <WRAP group><WRAP half column> | <WRAP pagebreak></WRAP> <WRAP group><WRAP half column> |
| <WRAP right><panel type="default"> Abb. 6 \\ {{drawio>pic3_5_2_Aufgabe6.svg}} </panel></WRAP> </WRAP></WRAP> | <WRAP right><panel type="default"> Abb. 6 \\ {{drawio>pic3_5_2_Aufgabe6.svg}} </panel></WRAP> </WRAP></WRAP> |
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| <WRAP onlyprint> \\ \\ \\ \\ \\ \\ \\ \\ </WRAP> <WRAP group><WRAP half column> | <button size="xs" type="link" collapse="sol3523">{{icon>eye}} Solution for (5) + (6)</button><collapse id="sol3523" collapsed="true"> |
| | Fig. 5 |
| | * No current flows through $R_3$, since no current can flow into the op-amp. Therefore, there is no voltage difference across $R_3$, and $R_3$ can be replaced by a short circuit. |
| | * $R_4$ and $R_2$ are in parallel and yield $R_g = \frac{2}{3} R_1$ |
| | * The gain thus becomes $A_V = \frac{R_g + R_1}{R_g} = 2.5$ |
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| | <WRAP right>{{url>https://www.falstad.com/circuit/circuitjs.html?ctz=CQAgjCAMB0l3BWcMBMcUHYMGZIA4UA2ATmIxAUgpABZsAoAQxExVr1rnZGPCQFowSMPHhRopUhkpxCKGsTx1wyUfQBOLDGzBg2rcBkJRVkDS3khs+7VbZURcczRodXtd7vunnnvR44wIxM0JwBzAMNjFw40DiozAHdIry0dfyS0kEIaLNTMmi53GO4zACULXOsouxMqQpUE8QR6bEI3Yo4EFDd4qHpkkqDjA2H+oA 500,400 noborder}} |
| | </WRAP> |
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| | ~~PAGEBREAK~~ ~~CLEARFIX~~ |
| | Fig. 6 |
| | * No current flows through $R_4$, since no current can flow into the op-amp. Therefore, there is no voltage difference across $R_4$, and $R_4$ can be replaced by a short circuit. |
| | * Since the inverting input is thus at 0 V, the output voltage becomes the maximum possible output voltage of the op-amp. |
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| | <WRAP right>{{url>https://www.falstad.com/circuit/circuitjs.html?ctz=CQAgjCAMB0l3BWcMBMcUHYMGZIA4UA2ATmIxAUgpABZsAoAQxExVr1rnZGPCQFowSMPHhRwyUfQBOLDG0I05bMGDZURcGcvBraNDqvWTI2mge7nDejfDMWj+wxkLi0WgOZPwL72g5UpgDuOo6sPq7BnFQWVtymAEo62GwoKEop4jEaWVDQCPTYhBxxFggoJQFQ9CFxYL7h9ZH0QA 500,400 noborder}} |
| | </WRAP></collapse> |
| | <WRAP group><WRAP half column> |
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| <WRAP right><panel type="default"> Abb. 7 \\ {{drawio>pic3_5_2_Aufgabe7.svg}} </panel></WRAP> </WRAP><WRAP half column> | <WRAP right><panel type="default"> Abb. 7 \\ {{drawio>pic3_5_2_Aufgabe7.svg}} </panel></WRAP> </WRAP><WRAP half column> |
| <WRAP right><panel type="default"> Abb. 8 \\ {{drawio>pic3_5_2_Aufgabe8.svg}} </panel></WRAP> </WRAP></WRAP> | <WRAP right><panel type="default"> Abb. 8 \\ {{drawio>pic3_5_2_Aufgabe8.svg}} </panel></WRAP> </WRAP></WRAP> |
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| | <button size="xs" type="link" collapse="sol3524">{{icon>eye}} Solution for (7) + (8)</button><collapse id="sol3524" collapsed="true"> |
| | Fig. 7 |
| | * The input voltage is applied across $R_4$, so a current $I = U_E / R$ flows through it. This current also flows through $R_3$. Therefore, the voltage across both is $2 \cdot U_E$. |
| | * The resistors $R_2$, $R_3$, and $R_4$ form $R_g = (R_3 + R_4)||R_2 = 2R||2R = R$ |
| | * Thus $R_g = R_1$, and the output voltage $U_A$ is twice the voltage across $R_g$, so the overall gain is $A_V = 4$ |
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| | <WRAP right>{{url>https://www.falstad.com/circuit/circuitjs.html?ctz=CQAgjCAMB0l3BWcMBMcUHYMGZIA4UA2ATmIxAUgpABZsAoAQxExVr1rnZGPCQFowSMPHhRopUoXhDJ2BLwgjR9AE4sMbMGDatwGQlGRw1GrTto0O2tlWWRTNK9yfWLd+I+c3L1g0bQTAHNffUNXFnwjBwB3MxBCGnifWM4qZwjnBwAleOxdFCT86M5wEpgEemxCDkyOBBRajipUiLB-PXbDByA 500,400 noborder}} |
| | </WRAP> |
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| | ~~PAGEBREAK~~ ~~CLEARFIX~~ |
| | Fig. 8 |
| | * The inverting and non-inverting inputs are shorted, so the output voltage is 0. |
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| | <WRAP right>{{url>https://www.falstad.com/circuit/circuitjs.html?ctz=CQAgjCAMB0l3BWcMBMcUHYMGZIA4UA2ATmIxAUgpABZsAoAQxExVr1rnZGPCQFowSMPHhRohFEhiThoyPQBOLDG0I0VbMGDZURcJZpD91R7LuQHlNGh1u172i-oXXHOhxzAZCUFvHoAc09wHxC0DioFAHdOKnsbO0j6ACUjEw0UFA0Mv3i9PPEEemxCOwSOBBQkvPpYxPAPVkbdOrM2ZtMFIA 500,400 noborder}} |
| | </WRAP> |
| | </collapse> |
| <WRAP pagebreak></WRAP> <WRAP group><WRAP half column> | <WRAP pagebreak></WRAP> <WRAP group><WRAP half column> |
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| <WRAP right><panel type="default"> Abb. 9 \\ {{drawio>pic3_5_2_Aufgabe9.svg}} </panel></WRAP> </WRAP><WRAP half column> </WRAP></WRAP> | <WRAP right><panel type="default"> Abb. 9 \\ {{drawio>pic3_5_2_Aufgabe9.svg}} </panel></WRAP> </WRAP><WRAP half column> </WRAP></WRAP> |
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| | <button size="xs" type="link" collapse="sol3525">{{icon>eye}} Solution for (9)</button><collapse id="sol3525" collapsed="true"> |
| | Fig. 9 |
| | * Between the inverting and non-inverting input, only $U_D \rightarrow 0$ is present. As long as $R_3 > 0$, this small voltage can exist there. Therefore, $R_3$ can be replaced by an open circuit. |
| | * Since no current flows through $R_4$, there is no voltage difference across $R_4$. Thus, $R_4$ can be replaced by a short circuit. |
| | * This results in a non-inverting amplifier with $A_V = \frac{R_2 + R_1}{R_2} = 1.5$ |
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| | <WRAP right>{{url>https://www.falstad.com/circuit/circuitjs.html?ctz=CQAgjCAMB0l3BWcMBMcUHYMGZIA4UA2ATmIxAUgpABZsAoAQxExVr1rnZGPCQFowSMPHhRopUnkqJJGQhEWjI9AE4saVQjQ1UwYNnvhrd4Qqe1RkcEzRod7tR-sPWV6uxxdOv8q2hsAcx9wP08WfCsVAHdOKkdwxxUAJVN+bDYwYjZ013i9KPEEemxCBwSOBBQHDioYkO8UTXADKHpYpq0dVhBLep6MlgxM837hs1MwUfbJ806QXLagA 500,400 noborder}} |
| | </WRAP> |
| | </collapse> |
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| </WRAP></WRAP></panel> | </WRAP></WRAP></panel> |
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