Op Amp ac circuit can also be analyzed with the same method with dc sources.
 Transform the circuit to the phasor or frequency domain.

Solve the problem using circuit techniques
 Kirchhoff,
 Nodal,
 Mesh,
 Superposition,
 Source Transformation, and
 Thevenin and Norton
 Transform the resulting phasor to the time domain.
Make sure to read what is ac circuit first.
Make sure to read:
 What is phasor
 Impedance and admittance
 Kirchhoff’s laws for ac circuit
 Power calculation in ac circuit
 Three phase circuit
And its applications:
Op Amp AC Circuits
Please remember, we will use ideal op amps here to ease the explanation. Take notice on the key of analyzing opamp circuits those are :
 No current enters either of its input terminals
 The voltage across its input terminals is zero
Let us review the examples below :
1. Determine v_{o}(t) for the op amp in Figure.(1a) if v_{s} = 3 cos 1000t V.
Figure 1. For example 1 : (a) the original circuit in the time domain, (b) its frequency domain 
Solution :
We first transform the circuit to the frequency domain, as drawn in Figure.(1b), where V_{s} = 3∠0^{o}, ω = 1000 rad/s. Applying KCL at node 1 we get
or
(1.1) 
At node 2, KCL gives
which leads to
(1.2) 
Substituting Equations.(1.2) to (1.1) gives
Thus
2. Compute the closedloop gain and phase shift for the circuit in Figure.(2). Assume that R_{1} = R_{2} = 10 kΩ, C_{1} = 2 uF, C_{2 }= 1 uF, and ω = 200 rad/s.
Figure 2 
Solution :
The feedback and input impedances are calculated as
Since the circuit in Figure.(2) is an inverting amplifier, the closedloop gain is given by
Substituting the given values of R_{1}, R_{2}, C_{1}, C_{2}, and ω, we get
Hence, the closedloop gain is 0.434 and the phase shift is 130.6^{o}.
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