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Electric Circuits II: (ELCT 401)
Instructors: Prof. Yasser Hegazy
Prof. Said Fouad
Lecture 1: Introduction
Course Outline
• Sinusoidal Steady State Analysis (AC Circuits)
• Power Calculations in AC circuits.
• Operational Amplifiers.
• Frequency Dependent Circuits
• Circuit Analysis in the Laplace Domain.
2
Study PlanWeek Topic Laboratories Tutorials
Remarks
Week I Introduction
Week II Circuit Elements in Phasor
Domain
Start of all Labs Start of All tutorials
Week III Circuit Analysis in Phasor Domain
Week IVLectures 4-5 AC Power
CalculationsWeek V
Week VI Operational Amplifiers
Midterm Exam ( no teaching )
Week VII Operational Amplifiers Applications
Week VIII Resonance
Week VIIII Filters No lecture for MCTR
Week X Circuit Analysis in “S” Domain No lectures for
IET and MET
Week XI Examples on “S” Domain
Week XII Revision
Course Activities
• Lectures
– Monday 2nd slot – H14 (MET II)
– Sunday 3rd slot – H14 (IET / MET I)
– Thursday 1st slot – H14 (MCTR I)
– Thursday 2nd slot – H14 (MCTR II)
• Tutorials.
One slot weekly, according to your schedule
• Laboratories.
One slot weekly, according to your schedule
4
Marking Scheme
• Assignments. 10 %
• Quizzes. 10 %
• Laboratories. 15 %
• Practical Project. 05 %
• Midterm Exam. 20 %
• Final Exam. 40 %
5
Resources
1.0 Text book
1. Electric Circuits Textbook by, Nilsson & Riedel. 10th Edition
• Chapters 5, 9 , 10 , 13, 14 and 15.
2. Charles K. Alexander and Matthew Sadiku, “Fundamentals of
Electric Circuits” 11th Edition, Mc. Graw Hill, 2017.
2.0 Lab manual
• Posted on the course webpage.
3.0 Webpage:
• All course information will be available online at
http://eee.guc.edu.eg/
6
Chapter I
Sinusoidal Steady State Analysis
“Alternating Current Circuits (A.C.)”
Objectives
• To review basic facts about sinusoidal signals.
• To introduce Phasors and convert the time domain
sinusoidal waveforms into Phasors.
• To develop the phasor relationships for the basic
circuit elements.
• To solve electric circuits in phasor domain.
8
Sinusoids
• A sinusoid is a signal that has the form of the sine or cosine
function.
• A general expression for the sinusoid,
whereVm = the amplitude of the sinusoidω = the angular frequency in radians/sФ = the phase
)sin()( tVtv m
Sinusoids
10
SinusoidsA periodic function is one that satisfies v(t) = v(t + nT), for all t and for all integers n.
HzT
f1
f 2
• Only two sinusoidal values with the same frequency can be
compared by their amplitude and phase difference.
• If phase difference is zero, they are in phase; if phase
difference is not zero, they are out of phase.
The Phasor
• A phasor is a complex number that
represents the amplitude and phase
of a sinusoid.
• It can be represented in one of the
following three forms:
12
rz
jrez
)sin(cos jrjyxz a. Rectangular
b. Polar
c. Exponential22 yxr
x
y1tanwhere
Phasor
• Transform a sinusoid to and from the time domain to the phasor domain:
(time domain) (phasor domain)
)cos()( tVtv m mVV
• Amplitude and phase difference are two principal concerns in the study of
voltage and current sinusoids.
• Phasor will be defined from the cosine function in all our proceeding study.
• If a voltage or current expression is in the form of a sine, it will be changed
to a cosine by subtracting from the phase.
Example:
Transform the following sinusoids to phasors:
i = 6 Cos(50t – 40o) A
v = –4 Sin(30t + 50o) V
Solution:
a. I A
b. Since –sin(A) = cos(A+90o);
v(t) = 4cos (30t+50o+90o) = 4cos(30t+140o) V
Transform to phasor => V V
406
1404
Example
Transform the sinusoids corresponding to phasors:
a.
b.
V 3010 V
A j12) j(5 I
Solution:
a) v(t) = 10cos(t + 210o) V
b) Since
i(t) = 13cos(t + 22.62o) A
22.62 13 )12
5( tan 512 j512 122
I
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Phasor
The differences between v(t) and V:
• v(t) is instantaneous or time-domain representation
V is the frequency or phasor-domain representation.
• v(t) is time dependent, V is not.
• v(t) is always real with no complex term, V is generally
complex.
Note: Phasor analysis applies only when frequency is constant; when
it is applied to two or more sinusoid signals only if they have
the same frequency.
Phasor Domain Analysis Approach
Have a Wonderful Semester
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