Circuit Theory I
Elec 105
Study guide for students
using
Introductory Circuit Analysis, 12th Ed. by Boylestad
Lecture Overview
• Introduction
• Voltage and Current
• Resistance
• Ohm’s Law, Power and Energy
• Series circuits
• Parallel circuits
• Series-Parallel circuits
• Methods of Analysis
• Mesh
• Nodal
• Network Theorems
• Capacitors
• Inductors
• Magnetic circuits
• Sinusoidal Alternating
Waveforms
Green—before midterm
Blue—after midterm
Lab Overview
• Using calculators/spreadsheets
/breadboards
• Using meters to measure
resistance, voltage, current
• Verifying Ohms Law, Power, and
Energy
• Series measurements
• Parallel measurements
• Series-Parallel measurements
• Verifying Network Theorems
• Testing Capacitors
• Testing Inductors
• Measuring magnetic circuits
Green—before midterm
Blue—after midterm
Student photos taking this course
Elec105 Sections 01/02 (left) and Section 05/06 (right) in Lecture at Wentworth Hall, Room 308
Week 1—Introduction
• Units of measurement
• Systems of units: English/metric
(MKS &CGS)/SI
• Significant figures, accuracy and
rounding off
• Using powers of ten for
calculations and with different
devices
Chapter homework: 4, 7, 11, 15, 16,
17, 18, 23, 29, 36, 42, 45 (all letters)
• Decimal representation: fixed &
floating point/scientific/
engineering
• Conversions: power of ten and
between systems of units
• Symbols and using conversion
tables
• Using calculators/spreadsheets
/computers/MatLab
• Sample problems
Homework demo Chapter 1
9/23/14
How to solve unit conversion problems, selecting the
right conversion factors or inverting it, which is more
accurate: miles or feet?
Using formulas and proportions to solve
equations. Recognizing errors. Ball parking the
answers to validate your answer by estimation
Homework Demo Chapter 1
9/23/14
How to recover from
errors in calculations,
decimal placement, not
reading the question
right, double-checking,
selecting units & tracking
unit cancellations
Week 2—Voltage and Current (V & I)
• Atomic structure of atoms:
• Protons, Neutrons, Electrons,
Shells
• Coulomb’s Law
• Forces and charges
• Conventional flow vs. electron
flow
• Voltage—what is voltage?
• Current—what is current?
Chapter homework: 2, 4a, 6, 8, 10,
13, 18, 16, 22, 29,
• Voltage sources
• Ampere-hour rating
• Conductors and insulators
• Semiconductors
• Ammeters
• Voltmeters
• Applications
• Sample problems
Preview Ch.3 power point for 9/17
Begin Multisim lab #1
Week 2 photos of board work
Formula 2.2 page 36 defining voltage-energy-charge relationship (left) and rest of board work thru slide 24
Week 2 photos of board work for rest of Ch2
Coulomb’s Law with units and constant k.
Battery life 2.8 and sample unit conversions
Week 3—Resistance (R)
• Resistance
• Formula
• Circular Mils (CM)
• Wire Tables
• Temperature effects
• Types of resistors
• Variable resistors
• Color coding
Chapter homework: 1a, 2a, 3a, 9a, 11a,
17a, 30a, 35a, 40, 45
• Conductance
• Ohmmeters
• Resistivity (r)
• Memristor, superconductors,
thermistors, photoconductive
cells, and varistors
• Sample problems
Images from Resistance lectures
Week 4—Ohm’s Law, Power, and Energy
• Ohm’s Law
• Power
• Joules
• horsepower
• Energy
• Formula
• Kilowatt hour (kWh)
Chapter homework: 5, 8, 13a, 20, 23, 36, 37,
40, 50, 56
• Efficiency
• Circuit breakers, GFCIs, and
Fuses
• Applications
• Sample problems
Board work for Ohm’s Law
Lab explanation
for Ohm’s Law
Lab on 9/22/14
I-V relationship
Developing I-V relationship as a linear relationship
Demonstrating the linear formula y=mx +b is I=(1/R)V+0
Chapter 4 board work on Power Theorems
Board work on how P=W/t is developed into working formulas for measurement instruments. Also
wrote up handout on information on page 107 in text on same material and emailed everyone.
Week 5—Series circuit
• Series resistors
• Series circuits
• Power distribution
• Voltage sources in series
• Kirchhoff’s Voltage Law (KVL)
• Voltage divider rule
• Interchanging series elements
Chapter homework: 2a, 4a, 7, 8,
9a, 12, 16, 18, 23a, 28a
• Notation
• Voltage regulation
• Internal resistance of voltage
sources
• Loading effect of instruments &...
• Applications
• Sample problems
Chapter 5 board work
Kirchhoff’s Voltage Law with examples
Voltage divider formula with examples
More board work from Chapter 5
More on voltage divider rule with add’l material
Week 6—Parallel Circuits
• Parallel resistors
• Parallel circuits
• Power distribution
• Kirchhoff’s Current Law (KCL)
• Current divider rule
• Voltage source in parallel
Chapter homework: 3a-c, 5e,
7, 9, 13, 16, 24, 27, 31, 40
• Open circuits
• Short circuits
• Voltmeter loading effects
• Summary table
• Applications
• Sample problems
Board work on Parallel circuit calculations
Week 7—Series-Parallel Circuits
• Series-parallel networks
• Reduce and return analysis
• Block diagram analysis
• Descriptive examples
• Ladder networks
• Voltage divider as a supply
source
Chapter homework: 3, 6, 11,
17, 27, 30, 33, 42
• Potentiometer loading
• Applications
• Ammeter, Voltmeter, and
Ohmmeter design
• Solving circuit problems using a
spreadsheet/calculator
• Sample problems
Midterm Review preparation
Midterm Review preparation
Week 8—Methods of Analysis
•
•
•
•
•
1st Lecture
Current sources & conversions
Current sources parallel/series
Branch-current analysis
Problems 1, 2, 7, 11, 15, 19
•
Lecture
• Use Power Point Nodal & Mesh
Analysis
• Mesh analysis
• Problems 32, 37, 39
2nd
• 3rd Lecture
• Use Power Point Nodal &
Mesh Analysis
• Nodal analysis
• Problems 40, 43, 48
•
•
•
•
4th Lecture
Bridge networks
Delta-Wye conversions
Problems 57, 66
Board work on simultaneous equation solutions
More board work on simultaneous equations
More board work on matrix solutions
Week 9—Network Theorems
• Superposition Theorem
• Thevenin Theorem
• Norton’s Theorem
• Maximum Power Transfer
• Millman’s Theorem
• Substitution Theorem
• Reciprocity Theorem
• Computer analysis
• Sample problems
Chapter homework: 1, 8, 9, 21, 30, 38, 43, 46
Homework after this point on was cancelled so we could concentrate on solving problems that students were
encountering. For example: six students in the morning section did not know how to calculate the area of a
circle much less do it in meters.
Week 10--Capacitors
• The electric field—e
• Capacitance
• Time constant: RC
• The current: iC
• What is it?
• Capacitance calculation via
• How to calculate it?
series/parallel formulas
• Capacitors
• Energy stored by a capacitor
• Transients in capacitive networks • Stray capacitances
• Initial conditions
• Applications
• Instantaneous values
• Sample problems
Chapter homework: 1, 6, 19, 23, 33,
39, 47, 49, 53, 56
Capacitors
Descriptive analysis of a capacitor
Behavior of capacitor from an overview perspective
and RC calculation.
Calculating the area for a 1 farad capacitors…
Behavior of
-t/τ
e
Behavior of capacitor from an overview
perspective and RC calculation.
Behavior of e^-t/tal
Week 11—Inductors
• Electromagnetic theory
• Calculation of Inductance
• Induced voltage vL
• Transients: storage/release
• Initial conditions
• Instantaneous values
Chapter homework: 1, 2, 3a,
4, 11, 29, 36, 38, 43
• Time constant: L/R
• Average induced voltage
• Inductance calculation via
series/parallel formulas
• Steady state conditions
• Energy stored by an inductor
• Samples problems
Lab combining Inductors and Capacitors
Week 12—Magnetic Circuits
• Magnetic field
• Reluctance
• Ohm’s Law for magnetics
• Magnetizing Force
• Hysteresis
• Ampere’s Circuital Law
Chapter homework: 3, 5, 7, 9, 14a, 17a, 19
• Flux Φ (Greek PHI) (pronounced as fee)
• Series magnetic circuits
• Air Gaps
• Series-parallel magnetic circuits
• Determining Φ
• Applications
• Sample problems
Week 13—Sinusoidal Alternating Waveforms
• Characteristics and definitions
• Frequency spectrum
• Sinusoidal waveform
• Voltage and current waveforms
Chapter homework: 1, 4, 8, 9 (don’t
redraw), 10-14 a only, 17a, 27a, 39, 47
• Phase relations
• Average value
• RMS values
• AC meter and instruments
• Sample problems