This is an example of a first order filter and the use of the AC analysis to find the frequency response of the magnitude and phase of a transfer function.

The Spice input file is given below. The opamp has been modeled as a voltage controlled voltage source (gain of 1E8), infinite input resistance and zero output resistance (ideal opamp). The input voltage V1 has a value of 1V so that the AC plot of the output voltage v(3) corresponds to the transfer function T(jw)=Vo/V1

Example AC Analysis

v1 1 0 ac 1

r1 1 2 10k

r2 2 3 100k

c 2 3 10n

e1 3 0 0 2 1e8

.ac dec 10 1 1e4

.plot ac vdb(3)

.plot ac vp(3)

.end

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