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

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

Large Scale Systems Electric Grid

Medium Scale System Death Star

Small Scale System Atomic Scale

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.

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

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

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.

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 1875-1896 a.k.a. “Hanging Judge Parker”

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

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

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

Volts By Convention, Earth = 0 volts a.k.a. Earth Ground or Ground Volts 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

Multimeter Example Voltage Displayed = Red Lead – Black Lead

Multimeter Example Voltage Displayed = Red Lead – Black Lead

Multimeter Example Voltage Displayed = Red Lead – Black Lead

Two Batteries in Series 1.5 v D Cell Multimeter VDC = Red Lead – Black Lead 1.5 v D Cell = 3 volts

Two Batteries in Series 1.5 v D Cell Multimeter VDC = Red Lead – Black Lead D Cell 1.5 v = 0 volts

Two Batteries in Parallel Multimeter VDC = Red Lead – Black Lead 1.5 v D Cell 1.5 v D Cell = 1.5 volts

Coulomb Named after Charles-Augustin de Coulomb 1736 – 1806 Source: Wikipedia Named after Charles-Augustin de Coulomb 1736 – 1806 French Physicist 1780's Investigated Static Charges (Repulsion & Attraction) Charge on Electron ≡ e ≡ 1.602 (10-19) Coulombs 1/e = 6.242(1018) Unit Charge = Charge on 6.242(1018) electrons

Amps Named after Andre-Marie Ampere 1775 – 1836 French Physicist 1820's Investigated Relationship Between Electricity & Magnetism Analogy Plumbing System Amps ≈ Water Flow Source: Wikipedia

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

Some Definitions Voltage: An Electro-motive Force Amps: Current Tries 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

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

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

Resistors Source: http://www.bcae1.com/resistrs.htm http://hyperphysics.phy-astr.gsu.edu/hbase/Electronic/rescarb.html

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

The "feel" Test, Version 1 9 V Battery on Your Tongue Tongue 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

The "feel" Test, Version 1B 12 V Car Battery on Your Tongue Tongue 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 >> 9 V Battery Max Current

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

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

9V Battery Model Ohm's Law says R = V/I = (0.5 V)/(0.020 A) = 25 Ω 20 mA R Ω 9 V 8.5 V Ohm's Law says R = V/I = (0.5 V)/(0.020 A) = 25 Ω

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