Circuit Theory I Elec 105 Study guide for students using Introductory Circuit Analysis, 12 th 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 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? 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 9/17 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 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 ed 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

Week 8—Methods of Analysis 1 st Lecture Current sources & conversions Current sources parallel/series Branch-current analysis Problems 1, 2, 7, 11, 15, 19 2 nd Lecture Use Power Point Nodal & Mesh Analysis Mesh analysis Problems 32, 37, 39 3 rd Lecture Use Power Point Nodal & Mesh Analysis Nodal analysis Problems 40, 43, 48 4 th 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 What is it? How to calculate it? Capacitors Transients in capacitive networks Initial conditions Instantaneous values Time constant: RC The current: i C 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 v L 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), a only, 17a, 27a, 39, 47