Chapter 10 – AC Circuits

Procedure:1. Transform sinusoidal time functions to phasors, and

convert element to complex impedance/admittance.2. Apply network reduction, or other circuit principles (KVL,

KCL, nodal, mesh, etc.) to determine desired response in phasor form.

3. Transform results to time functions.

Recall: Element Impedances and Admittances

Nodal Analysis: Example 1. Find ix using nodal analysis.

Recall: Nodal Analysis with Voltage Sources

Mesh Analysis Example 2. Find I0 using nodal analysis.

Recall Mesh Analysis with Current Sources:

Superposition:- Each source may have its own frequency impedances

of elements depend on which source is on. See Example 10.6

Source Transformation:

Thevenin’s Theorem

A linear two-terminal circuit can be replaced by an equivalent circuit consisting of a voltage source VTh in series with an impedance ZTh, where:

VTh = Voc = open-circuit voltage at the terminalsZTh = equivalent impedance at the terminals with all the independent sources turned off.

Example. Find Io using Thevenin’s Theorem.

Norton Equivalent Circuit

A linear two-terminal circuit can be replaced by an equivalent circuit consisting of a current source IN in parallel with an impedance ZN, where:

IN = Isc = short-circuit current through the terminalsZN = equivalent impedance at the terminals with all the independent sources turned off.

OP AMP AC Circuits: Example. Find the voltage gain Av = Vo/Vs.