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