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Inverting operational amplifier

Introduction

This example presents the operation of a standard inverting operational amplifier circuit.

Model description

In the above model, the feedback impedance is $R_f = 10 кОм$, the input impedance is $R_{in} = 1 кОм$. Hence, the gain is defined as $-\frac{R_f}{R_{in}} = -\frac{10^4}{10^3}=-10$.

ampinv_mod.png

Since the operational amplifier block realises an ideal device (i.e. with infinite gain), the defined gain is independent of the output load. Thus, when the input voltage amplitude is $0.1 В$, the output voltage increases to the amplitude $1 В$.

Modelling results

As a result of the simulation, the plots of input and output voltages will be as shown in the figure below.

ampinv_graph_2.png

As can be seen from the graphs, the instantaneous voltage at the output of the operational amplifier is inverted and amplified by a factor of 10.

Conclusion

In the example discussed, the circuit of an ideal inverting operational amplifier has been assembled and modelled.