Graphs – HW, Labs & Exam
Sinusoidal Steady State:
Circuit Analysis Tools
EGR 220, Chapter 10
April 5, 2016
•  Target audience – Sue F.; perhaps a firstyear EGR student; your sibling…
•  Make graphs very clear, neat, easy to
read and understand
o WELL – LABELED
o Title, axes, important data points, etc.
o YOU must completely discuss and explain in
your text, directing the reader to the figure
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Representing Impedance
Concept: Impedance
•  Z = V/I = R + jX
•  Physical phenomenon that impedes
the flow of electrons
•  Resistor: ZR = R ( + j0)
o Energy required to charge magnetic fields
o Energy required to charge electric fields
•  Inductor: ZL = j XL = _______
•  Equivalent impedance “seen” by an
energy source
•  Capacitor: ZC = – j XC = _______
o Zeq as seen from different terminals in a
circuit (as with Req)
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Simple Calcs with Impedance
Equivalent Impedance
•  Find i(t) and v(t) à set up solution
•  Find Zin à method only
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Nodal Analysis
Chapter 10: Sinusoidal Steady-State
•  Apply all dc circuit analysis tools to
•  Find the voltage Vo
o Circuits with complex impedances
o Circuits with sinusoidal signals
o Ohm’s Law:
•  V = IZ
•  With Xc and XL in units of Ω
o Nodal & mesh analysis (KVL, KCL)
o Thevenin equivalent circuit
o Superposition, source transformation...
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Mesh Analysis
Plot in Complex Plane
•  Find the current io
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Thevenin Equivalent
Plot in Complex Plane
•  Find the equivalent circuit
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Source Transformation
•  Find vo(t)
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Summary
Use of Phasors
•  Impedance and the flow of electrical
energy in matter
•  Tools applied to sinusoidal steady state
analysis
•  Focus on forced response only
o Transient/natural response in time domain
•  Use Ohm’s and Kirchhoff’s laws, in the
phasor/frequency domain, to find a
steady-state solution
o Ohm’s law
o Nodal and mesh analysis (KCL and KVL)
o Superposition
o Source transformation
o Thevenin and Norton
o This does not require knowing initial values
o Use complex math instead of differential
equations (typically is easier)
•  Sinusoidal Steady-State applications
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