1 ENGS2613 Intro Electrical Science Week 1, Lectures 1 & 2Read Chapter 1 Problems 1.2, 10, 11 Quiz #1, 27 January

2 Student Engineering SocietiesArchitecture Biosystems & Agriculture Chemical Civil & Environmental Electrical & Computer Industrial Materials Science Mechanical & Aerospace Attend Student Branch Eng Society Meetings & Get < 10 points Extra Credit Selfie; or Note from Pres, VP, or Sec stating you attended 3, 3, 4 basis

3 Large Scale Systems Electric Grid

4 Medium Scale System Death Star

5 Small Scale System Atomic Scale

6 Tentative Grading 10 x 10 point full period Friday events#1 on Friday 27 January 2 x 100 point full period Friday Exams 1 x 30 point design problems 1 x 150 point Comprehensive Final 480 points Total 90%, 80%, etc. for A, B, C... Will be curved.

7 Grading In Class: Quizzes, Events, Tests, Final Exam Closed Book & Notes < 3 pages of "Assistance" Sheets Allowed Calculators Allowed, Smart Phones Not Ungraded Homework: Assigned most every class Not collected Answers Available Online Payoff: Tests & Quizzes

8 Why work the ungraded Homework problems?An Analogy: Electrical Science vs. Soccer Reading text = Reading a book about Soccer Looking at problem solutions = watching others play soccer Working the problems = practicing or playing soccer Friday Events = Exhibition Game Test = Big Game

9 To succeed in this class...Show some self-discipline!! Important!! For every hour of class put in 1-2 hours of your own effort. PROFESSOR'S LAMENT If you put in the time You should do fine. If you don't, You likely won't.

10 Cheating Don’t do it! If caught, expect to get an ‘F!’ for the course.My idol: Judge Isaac Parker U.S. Court: Western District of Arkansas a.k.a. “Hanging Judge Parker”

11 Primary Goal Ability to Analyze & Design Simple Electric CircuitsUnderstand Basic Electrical Concepts Ability to Analyze & Design Simple Electric Circuits

12 Volts Named after Allesandro Volta 1745 – 1827 Italian PhysicistInvented Electric Battery Analogy Plumbing System Volts ≈ Water Pressure Source: Wikipedia

13 Volts Difference twixt top & bottom = 1.5 v [Top is 1.5v higherCan be +, -, or 0 Measured relative to something Difference twixt top & bottom = 1.5 v [Top is 1.5v higher than bottom] Source: Wikipedia

14 Volts By Convention, Earth = 0 volts a.k.a. Earth Ground or GroundVolts may be a constant value a.k.a. Volts DC (DC = Direct Current) Volts may be variable over time a.k.a. Volts AC (AC = Alternating Current) Source: Wikipedia

15 Multimeter Example Voltage Displayed = Red Lead – Black Lead

16 Multimeter Example Voltage Displayed = Red Lead – Black Lead

17 Multimeter Example Voltage Displayed = Red Lead – Black Lead

18 Two Batteries in Series1.5 v D Cell Multimeter VDC = Red Lead – Black Lead 1.5 v D Cell = 3 volts

19 Two Batteries in Series1.5 v D Cell Multimeter VDC = Red Lead – Black Lead D Cell 1.5 v = 0 volts

20 Two Batteries in ParallelMultimeter VDC = Red Lead – Black Lead 1.5 v D Cell 1.5 v D Cell = 1.5 volts

21 Coulomb Named after Charles-Augustin de Coulomb 1736 – 1806Source: Wikipedia Named after Charles-Augustin de Coulomb 1736 – 1806 French Physicist 1780's Investigated Static Charges (Repulsion & Attraction) Charge on Electron ≡ e ≡ (10-19) Coulombs 1/e = 6.242(1018) Unit Charge = Charge on 6.242(1018) electrons

22 Amps Named after Andre-Marie Ampere 1775 – 1836 French Physicist1820's Investigated Relationship Between Electricity & Magnetism Analogy Plumbing System Amps ≈ Water Flow Source: Wikipedia

23 Joule Named after James Prescott Joule 1818 - 1889British Brewer & Physicist 1840 Began investigating energy & power to improve Brewery's Efficiency Source: Wikipedia

24 Some Definitions Voltage: An Electro-motive Force Amps: CurrentTries to move Electrons around Amps: Current Flow of Electrical Charge (Electrons) Joules: Energy 1 Joule = 1 Volt * 1 Coulomb Power: Energy per unit Time 1 Watt = 1 Joule/second

25 Current Flow + ↑ Electron Flow (Negative Charge) Safety Tip:D Cell ↑ Electron Flow (Negative Charge) Safety Tip: Don't Try This At Home -

26 Joules/Second = Watt Named after James Watt 1736 - 1819Scottish Mechanical Engineer > 1759 Began investigating efficiency of Steam Engines Source: Wikipedia

27 Resistors Source: http://www.bcae1.com/resistrs.htm

28 Ohm's Law Named after Georg Ohm 1789 - 1854German Physicist University Professor Investigated relationship between voltage & current Results published in 1827 V = I R Source: Wikipedia

29 The "feel" Test, Version 1 9 V Battery on Your TongueTongue Resistance ≈ 16,000 Ω Ohm's Law: I = V/R = 560 μa Pain Rating 0 = No Pain 1 = Notice When Bored 2 = Uncomfortable, but no big deal 3 = Uncomfortable but Tolerable 4 = Very Uncomfortable & Want it to Stop … 10 = Don't Notice Anything But Pain

30 The "feel" Test, Version 1B 12 V Car Battery on Your TongueTongue Resistance ≈ 16,000 Ω Ohm's Law: I = V/R = 750 μa Pain Rating About Same as 9 V Battery Safety Tip: Don't Try This at Home! Can End Up in Hospital if Leads Touch Each Other Car Battery Max Current >> V Battery Max Current

31 Car Battery Model Ohm's Law says R = V/I = (0.5 V)/(20 A) = 0.025 Ω

32 Car Battery Model Ohm's Law says I = V/R = (12 V)/(0.025 Ω) = 480 A

33 9V Battery Model Ohm's Law says R = V/I = (0.5 V)/(0.020 A) = 25 Ω20 mA R Ω 9 V 8.5 V Ohm's Law says R = V/I = (0.5 V)/(0.020 A) = 25 Ω

34 9 V Battery Model Ohm's Law says I = V/R = (9 V)/(25 Ω) = 360 mA 25 Ω

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