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lab05_en:inverting_op-amp_basics_amplification [2026/04/01 16:51] – mexleadminlab05_en:inverting_op-amp_basics_amplification [2026/04/28 16:21] (current) – [Analysis of inverting input currents] mexleadmin
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-$U_{\rm DD}{\rm~=~10~V},~U_{\rm SS}{\rm~=~-10~V},~R_{\rm 1}{\rm~=~10~k\Omega}$+$U_{\rm DD}{\rm~=10~V},~U_{\rm SS}{\rm~=-10~V},~R_{\rm 1}{\rm~=10~k\Omega}$
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-Calculate the necessary value for $R_{\rm 2}$, so that the Output $U_{\rm OUT}$ is 5 V.+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 $U_{\rm IN}$. Use the supply voltage of the operational amplifier for $U_{\rm IN}$.
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 +$R_{\rm 2}{\rm~=}$
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-$R_{\rm 2}{\rm~=}$+== Analysis of inverting input currents ==
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 +{{drawio>lab05:Fig-30_inverting_op-amp_inv_input.svg}}
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-== Investigation of inverting input ==+<imgcaption Fig-30_inverting_op-amp_inv_input | Inverting Op-Amp: Analysis of currents of the inverting input> </imgcaption>
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-{{drawio>lab05:Fig-30_inverting_op-amp_inv_input.svg}}+$U_{\rm DD}{\rm~=10~V},~U_{\rm SS}{\rm~=-10~V},~R_{\rm 1}{\rm~=10~k\Omega}$\\ \\ 
 +Use the values from <imgref Fig-20_inverting_op-amp> for $U_{\rm IN},~U_{\rm OUT},~R_{\rm 2}$.
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-<imgcaption Fig-30_inverting_op-amp_inv_input | Inverting Op-Amp: Investigate inverting input> </imgcaption>+\\ 
 +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). 
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 +$U_{\rm 1}{\rm~=}$ 
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 +$U_{\rm 2}{\rm~=}$\\ 
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 +$I_{\rm 1}{\rm~=}$ 
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 +$I_{\rm 2}{\rm~=}$ 
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 +$I_{\rm N12}{\rm~=}$ 
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 +== Analysis of inverting input voltages == 
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 +{{drawio>lab05:Fig-40_inverting_op-amp_inv_input_virt_gnd.svg}} 
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 +<imgcaption Fig-40_inverting_op-amp_inv_input_virt_gnd | Inverting Op-Amp: Analysis of virtual GND of the inverting input> </imgcaption>
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 $U_{\rm DD}{\rm~=10~V},~U_{\rm SS}{\rm~=-10~V},~R_{\rm 1}{\rm~=10~k\Omega}$\\ \\ $U_{\rm DD}{\rm~=10~V},~U_{\rm SS}{\rm~=-10~V},~R_{\rm 1}{\rm~=10~k\Omega}$\\ \\
-For $U_{\rm IN},~U_{\rm OUT}~R_{\rm 2}$ use the values from <imgref Fig-30_inverting_op-amp_inv_input>.+Use the values from <imgref Fig-20_inverting_op-amp> for $U_{\rm IN},~U_{\rm OUT},~R_{\rm 2}$. 
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 +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 $U_{12}$. 
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 +$U_{\rm 1}{\rm~=}$ 
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 +$U_{\rm 2}{\rm~=}$ 
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 +$U_{\rm OUT}{\rm~=}$ 
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 +Calculated $U_{\rm 12}{\rm~=}$ 
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 +Measured $U_{\rm 12}{\rm~=}$
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 +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?\\
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- +What happens if you short-circuit $R_2$ (the feedback resistor)?\\ 
- +Experimentally verify this effect and explain the observed behavior regarding the output voltage.\\ 
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-- Virt masse messen\\ +${\rm ................................................................................................}$ \\ \\ 
-- r2 kurzschluss+${\rm ................................................................................................}$ \\ \\ 
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