DW EditShow pageOld revisionsBacklinksAdd to bookExport to PDFFold/unfold allBack to top This page is read only. You can view the source, but not change it. Ask your administrator if you think this is wrong. ==== Inverting Operational Amplifier ==== == Gain of Op-Amp == Build the following circuit in <imgref Fig-20_inverting_op-amp> with the power supply and a multimeter. {{drawio>lab05:Fig-20_inverting_op-amp.svg}} \\ <imgcaption Fig-20_inverting_op-amp | Inverting Op-Amp> </imgcaption> \\ \\ $U_{\rm DD}{\rm~=10~V},~U_{\rm SS}{\rm~=-10~V},~R_{\rm 1}{\rm~=10~k\Omega}$ \\ \\ Calculate the necessary value for $R_{\rm 2}$, so that the Output $U_{\rm OUT}$ is +5 V. Use the supply voltage of the operational amplifier for $U_{\rm IN}$. \\ \\ \\ $U_{\rm IN}{\rm~=}$ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ $R_{\rm 2}{\rm~=}$ \\ \\ \\ == Analysis of inverting input currents == \\ \\ {{drawio>lab05:Fig-30_inverting_op-amp_inv_input.svg}} \\ <imgcaption Fig-30_inverting_op-amp_inv_input | Inverting Op-Amp: Analysis of currents of the inverting input> </imgcaption> \\ \\ $U_{\rm DD}{\rm~=10~V},~U_{\rm SS}{\rm~=-10~V},~R_{\rm 1}{\rm~=10~k\Omega}$\\ \\ Use the values from <imgref Fig-20_inverting_op-amp> for $U_{\rm IN},~U_{\rm OUT},~R_{\rm 2}$. \\ \\ Complete the arrows in the scematic of the circuit.\\ Determine the the currents $I_{\rm 1}$ and $I_{\rm 2}$ indirectly by measuring the voltage across known resistors\\ and calculate the algebraic sum of the currents at node $N_{\rm {12}}$ using Kirchhoff’s Current Law (KCL). \\ \\ $U_{\rm 1}{\rm~=}$ \\ \\ \\ $U_{\rm 2}{\rm~=}$\\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ $I_{\rm 1}{\rm~=}$ \\ \\ \\ $I_{\rm 2}{\rm~=}$ \\ \\ \\ $I_{\rm N12}{\rm~=}$ \\ \\ \\ == Analysis of inverting input voltages == \\ \\ \\ {{drawio>lab05:Fig-40_inverting_op-amp_inv_input_virt_gnd.svg}} \\ \\ <imgcaption Fig-40_inverting_op-amp_inv_input_virt_gnd | Inverting Op-Amp: Analysis of virtual GND of the inverting input> </imgcaption> \\ \\ $U_{\rm DD}{\rm~=10~V},~U_{\rm SS}{\rm~=-10~V},~R_{\rm 1}{\rm~=10~k\Omega}$\\ \\ Use the values from <imgref Fig-20_inverting_op-amp> for $U_{\rm IN},~U_{\rm OUT},~R_{\rm 2}$. \\ \\ \\ Complete the reference arrows in the scematic of the circuit.\\ Take the values for $U_{\rm 1},~U_{\rm 2},~U_{\rm OUT}$ from <imgref Fig-30_inverting_op-amp_inv_input>.\\ Calculate the voltage $U_{12}$ using Kirchhoff's Voltage Law (KVL) within the circuit loop.\\ Verify your calculated result by measuring $U_{12}$. \\ \\ \\ $U_{\rm 1}{\rm~=}$ \\ \\ \\ $U_{\rm 2}{\rm~=}$ \\ \\ \\ $U_{\rm OUT}{\rm~=}$ \\ \\ \\ Calculated $U_{\rm 12}{\rm~=}$ \\ \\ \\ Measured $U_{\rm 12}{\rm~=}$ \\ \\ \\ Analyse the physical significance of the potential at $N_{12}$ relative to GND (defined as $U_{12}$) in the context of the operational amplifier's input configuration. What do you observe?\\ \\ \\ ${\rm ................................................................................................}$ \\ \\ ${\rm ................................................................................................}$ \\ \\ ${\rm ................................................................................................}$ \\ \\ ${\rm ................................................................................................}$ \\ \\ ${\rm ................................................................................................}$ \\ \\ ${\rm ................................................................................................}$ \\ \\ ${\rm ................................................................................................}$ \\ \\ ${\rm ................................................................................................}$ \\ \\ ${\rm ................................................................................................}$ \\ \\ ${\rm ................................................................................................}$ \\ \\ ${\rm ................................................................................................}$ \\ \\ \\ What happens if you short-circuit $R_2$ (the feedback resistor)?\\ Experimentally verify this effect and explain the observed behavior regarding the output voltage.\\ \\ \\ ${\rm ................................................................................................}$ \\ \\ ${\rm ................................................................................................}$ \\ \\ ${\rm ................................................................................................}$ \\ \\ ${\rm ................................................................................................}$ \\ \\ ${\rm ................................................................................................}$ \\ \\ ${\rm ................................................................................................}$ \\ \\ ${\rm ................................................................................................}$ \\ \\ ${\rm ................................................................................................}$ \\ \\ ${\rm ................................................................................................}$ \\ \\ ${\rm ................................................................................................}$ \\ \\ ${\rm ................................................................................................}$ \\ \\ CKG Edit