{{fa>pencil?32}} 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. __Assumptions__ * $R_1 = R_3 = R_4 = R$ * $R_2 = 2 \cdot R$ * $U_\rm I$ comes from a low-resistance source * $U_\rm O$ is due to a high-resistance consumer __Exercises__ - Enter the voltage gain $A_\rm V$ for each circuit. A detailed calculation as before is not necessary. - For Figure 7, indicate how the voltage gain can be determined. - Generalize with the following justifications: - How has a short circuit of the two OPV inputs must be taken into account? - How do resistances have to be considered in the following cases: - with one terminal (so "one connector") directly and exclusively on an OPV input, - with both terminals each directly connected to an OPV input. - In which circuits do resistors $R_3$ and $R_4$ represent an unloaded voltage divider? To approach the problems, you should try to use the knowledge from the inverting amplifier. It can be useful to simulate the circuits via [[http://www.falstad.com/circuit/|Falstad-Circuit]] or Tina TI. In the first two circuits, tips can be seen under the illustration as support. \\ \\ **__Important__**: As always in your studies, you should try to generalize the knowledge gained from the task. **Tipps** * 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? Abb. 1 \\ {{drawio>pic3_5_2_Aufgabe1.svg}} \\ \\ \\ \\ \\ \\ \\ \\ ++++ Hints| * How high is the current flow into the inverting and non-inverting input of an ideal operational amplifier? 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 enough current at the output so that the required minimum voltage is between the inverting and non-inverting input $U_\rm D$ results. How big can $U_\rm D$ be accepted? Can this voltage also via a resistor ($R_4$) being constructed? ++++ Abb. 2 \\ {{drawio>pic3_5_2_Aufgabe2.svg}} \\ \\ \\ \\ \\ \\ \\ \\ ++++ Hints| * How much current must flow through $R_4 = R$ so that the expected voltage $U_4$ results? * How much current must flow through $R_2 = 2 \cdot R$ fließen? * How much current must flow through $R_1 = R$? How high is the voltage at $R_1$? ++++ \\ \\ \\ \\ \\ \\ \\ \\ Abb. 3 \\ {{drawio>pic3_5_2_Aufgabe3.svg}} Abb. 4 \\ {{drawio>pic3_5_2_Aufgabe4.svg}} Abb. 5 \\ {{drawio>pic3_5_2_Aufgabe5.svg}} Abb. 6 \\ {{drawio>pic3_5_2_Aufgabe6.svg}} \\ \\ \\ \\ \\ \\ \\ \\ Abb. 7 \\ {{drawio>pic3_5_2_Aufgabe7.svg}} Abb. 8 \\ {{drawio>pic3_5_2_Aufgabe8.svg}} Abb. 9 \\ {{drawio>pic3_5_2_Aufgabe9.svg}}