Circuit Theory IElec 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

• 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

Chapter homework: 4, 7, 11, 15, 16, 17, 18, 23, 29, 36, 42, 45 (all letters)

Homework demo Chapter 19/23/14

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?

• Voltage sources• Ampere-hour rating• Conductors and insulators• Semiconductors• Ammeters • Voltmeters• Applications• Sample problems

Chapter homework: 2, 4a, 6, 8, 10, 13, 18, 16, 22, 29,

Preview Ch.3 power point for 9/17Begin 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

• Conductance• Ohmmeters• Resistivity (r)• Memristor, superconductors,

thermistors, photoconductive cells, and varistors• Sample problems

Chapter homework: 1a, 2a, 3a, 9a, 11a, 17a, 30a, 35a, 40, 45

Images from Resistance lectures

Week 4—Ohm’s Law, Power, and Energy• Ohm’s Law• Power• Joules• horsepower

• Energy• Formula • Kilowatt hour (kWh)

• Efficiency• Circuit breakers, GFCIs, and

Fuses• Applications• Sample problems

Chapter homework: 5, 8, 13a, 20, 23, 36, 37, 40, 50, 56

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

• Notation• Voltage regulation • Internal resistance of voltage

sources• Loading effect of instruments &...• Applications• Sample problems

Chapter homework: 2a, 4a, 7, 8, 9a, 12, 16, 18, 23a, 28a

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

• Open circuits• Short circuits• Voltmeter loading effects• Summary table• Applications• Sample problems

Chapter homework: 3a-c, 5e, 7, 9, 13, 16, 24, 27, 31, 40

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

• Potentiometer loading• Applications• Ammeter, Voltmeter, and

Ohmmeter design• Solving circuit problems using a

spreadsheet/calculator• Sample problems

Chapter homework: 3, 6, 11, 17, 27, 30, 33, 42

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

• 2nd Lecture• Use Power Point Nodal & Mesh

Analysis• Mesh analysis• Problems 32, 37, 39

• 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, 46Homework 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 • What is it?• How to calculate it?

• Capacitors • Transients in capacitive networks• Initial conditions• Instantaneous values

• Time constant: RC• The current: iC

• Capacitance calculation via series/parallel formulas• Energy stored by a capacitor• Stray capacitances• Applications• Sample problems

Chapter homework: 1, 6, 19, 23, 33, 39, 47, 49, 53, 56

Capacitors

Calculating the area for a 1 farad capacitors…

Behavior of capacitor from an overview perspective and RC calculation.

Descriptive analysis of a capacitor

Behavior of e-t/τ

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

• Time constant: L/R• Average induced voltage• Inductance calculation via

series/parallel formulas• Steady state conditions• Energy stored by an inductor• Samples problems

Chapter homework: 1, 2, 3a, 4, 11, 29, 36, 38, 43

Lab combining Inductors and Capacitors

Week 12—Magnetic Circuits• Magnetic field• Reluctance• Ohm’s Law for magnetics• Magnetizing Force• Hysteresis• Ampere’s Circuital Law

• Flux Φ (Greek PHI) (pronounced as fee)

• Series magnetic circuits• Air Gaps• Series-parallel magnetic circuits• Determining Φ• Applications• Sample problems

Chapter homework: 3, 5, 7, 9, 14a, 17a, 19

Week 13—Sinusoidal Alternating Waveforms• Characteristics and definitions• Frequency spectrum• Sinusoidal waveform• Voltage and current waveforms

• Phase relations• Average value• RMS values• AC meter and instruments• Sample problems

Chapter homework: 1, 4, 8, 9 (don’t redraw), 10-14 a only, 17a, 27a, 39, 47