:<math> \frac{ v_{out} }{ v_{in} } = - \frac{1/sC_1}{R_1} = -\frac{1}{ s\left( R_1C_1 \right)} </math>
which represents a integral operator in the Laplace s-domain. This circuit is very similar to the Op Amp differentiator except for the fact that the timing resistor and capacitor have switched places.
An equivalent macromodel of the above circuit is given in the following figure. This is , which represents [[RF.Spice]]'s "Analog Integrator Block". In this model, the ideal Op Amp has been replaced with the linear controlled voltage source E2:
:<math> E_2 = (-10^9) . v_{R_5} </math>
<table>
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<td> [[Image:Diff4Integ2.png|thumb|700px|RF.Spice's "Analog DifferentiatorIntegrator" block circuit.]] </td>
</tr>
</table>