ELEC130 Electrical Engineering 1

1. ELEC130 Electrical Engineering 1 Gunilla Burrowes Fernando Martinez EA G24 EE 102 (p) 4921 6352 4921 6149 email gunilla@ee fmm@ecemail Mon &Fri 2-3pm Help Desk HELP - EA G08 - during office hours

2. Material • 5 modules • 1 - Introductory Circuit Techniques Week 1 & 2 • 2 - DC Circuit Tools Week 2 3 & 4 • 3 - AC Circuit Tools Week 5 & 6 • 4 - Applications in Power Week 7 & 8 • 5 - Applications in Communications & Week 9 10 11 Instrumentation Week 12 & 13 • Electronic Workbench: Faculty PC’s Rm. ES210 - Go to Diomedes • Login: cstudentnumber Password: access keys on students card + daymonth (ddmm) of birth • TopClass: http://www.newcastle.edu.au:86/topclass/ • Username: first name.last name • Password: date of birth ddmmyy • Email: first name.last name@studentmail

3. Lectures • 2 hour / week for 13 weeks - Monday 5 -7pm • Quizzes - Weeks 3 6 8 11 13 • Course Information Booklet • Student Responsibility • Survey

4. Student Responsibility • Expect CIVIL Behavior • Work consistently • Progressive assessment • Teaching / Learning • Rote Learning • Where to go for help • Material may not always seem relevant

5. Its Up To You • The onus is shifted to you to “learn” (independently) • Majority of learning will take place when you tackle the subject material • BURY NOW the natural tendency to assume a passive role (waiting to be taught)

6. Text & References • Course information Booklet & Safety Notes $12.00 Purchase after this lecture - Foyer EA • Several Alternative Texts • Floyd - Principles of Electric Circuits • Dorf - Introduction to Electric Circuits • Hambley - Electrical Engineering • Johnson - Electric Circuit Analysis • Student Problem Sets - Library • Text references • Study Guide

7. Tutorials • 1 hours / week. Start next week • Check your group on Noticeboard Foyer EA You must Enroll Tonight • ASK QUESTIONS • Electronic Workbench - ES 210 • Introduction - Tutorial 2 Week 3 • Matrix - textbook • Tutorial 1

8. Laboratory • 2 hours / week - start next week • Voluntary Laboratory THIS WEEK • Check your group on Noticeboard Foyer EA You Must Enroll Tonight - Foyer EA • EE 103(a) • 9 laboratory exercises (Lab 1 goes for 2 weeks) • 2 practical tests - 15 % each (Total 30%) • All experiments are considered “examinable” • Keep a Laboratory diary

9. Laboratory • Attendance Sheets • Safety - notes will be attached to course information booklet- READ THEM • Use Common Sense • Keep the Laboratory Tidy • BE PREPARED

10. Help Desk - EE 102 / EE 103 Monday 9 - 11 am Wednesday 8 - 9 am 1 - 2 pm 8 - 9 pm

11. Assessment • Final grade for ELEC 130 will be • 5 quizzes @ 4% each 20% • 2 laboratory tests @ 15% 30% • June Exam @ 50% 50%

12. Engineering • Concerned with creation of solutions to problems, based on science and technology • Systems Engineering • emphasises a wholistic design methodology • encompasses the whole life cycle of the product • Role taken on by engineering in technology-based enterprises • creative element to convert a need into a service or product • integration of all processesinto a single coherent process

13. Multi-disciplinary & Integrating Nature

14. Market Marketing, sales and support Market research Engineering Need Service Technology, R & D Engineering as a Process

15. Changing Nature of Engineering • The essence of engineering is a product of the human mind • For the mind to be creative, it must operate on concepts (not just facts) • Swing back to the wholistic view • complexity of the interaction with society • rapid and fascinating development of engineering science

16. Engineering • Involves two complementary subjects • the body of knowledge known as engineering science • the process of applying that knowledge

17. Aims of ELEC 130 • To study the concepts of basic electrical elements & circuits • Start with laws of physics to derive simple ‘rules’ for electrical circuits • Same rules apply to • ‘light’ current i.e. computers, communication • ‘heavy’ current i.e. power grid, motors

18. Overview of DC Circuits • Units & Notation • What is a circuit? • What is Charge / Current? • What is Voltage? • Voltage & Current sources • Power • Resistance • Ohm’s Law

19. Units • SI system - kg,m,s • Others derived from these - Volts, Farads • Scaling of Units • p pico 10-12 • n nano 10-9 •  micro 10-6 • m milli 10-3 • _ unit 1 • K kilo 103 • M mega 106 • G giga 109

20. Notation • Time varying quantities - lower case e.g. v(t), i(t) • sometimes assume time - v(t) = v • Time invariant quantities - upper case e.g. V, R, • Remember to include units of measure e.g. 15 Volts

21. What is a circuit? • In ELEC130 we assume that a circuit comprises of two or more elements connected by electrical conductors. • Electrical conductors allow electricity to flow (unimpeded) between elements • Electricity must flow in a CLOSED path or circuit

22. Open Circuit • A ‘Break’ in a circuit is called an open circuit

23. Short Circuit • A ‘bypass’ of an element is called a short circuit

24. Different Geography • Two circuits may have the same topology but different geography

25. Charge • Charge is the phenomenon giving rise to those forces observed between electrical charged bodies. There are 2 kinds of charges: pos & neg • Symbol Q (constant) or q(t) (time varying) • Defined in terms of the charge on 1 electron ~=1.6x10-19 Coulombs • or stated as Charge on 6.2x1018 electrons is 1 Coulomb

26. Current • Motion of charge constitutes an electric current • Conventional current is the flow of positive charges • Electron current is negative charges • Measure of rate of flow of charge 1 Ampere = 1 Coulomb/sec • or Charge is the sum or ‘accumulation’ of current • Symbol I i(t)

27. circuit 3 A Current cont.. • The primary purpose of electric circuits is to move or transfer charges along specific paths circuit = - 3 A

28. Voltage • Fix one Coulomb of charge in space … energy input (work) is required to bring another Coulomb of charge from a point A to a new point B closer to the fixed charge ……. the potential energy difference between points B & A is known as voltage: • 1 Volt = 1 Joule / Coulomb • Charge tends to flow from a higher voltage (potential) to a lower voltage - resulting charge flow is current • Symbol V v(t)

29. Power • Power is  energy /  time • P = VI Watts • p = v(t).i(t) W • i.e. need voltage and current (at the same time) to do work • Power can be +ve and -ve; it can be ‘absorbed’ or delivered • Symbol: P p(t) Units: Watts W

30. i(t) + v(t) - Circuit or element Power Convention • If v(t)  0 and i(t) 0 then p  0 • Power is said to be absorbed by the circuit • NB polarity of voltage and direction of current

31. V A Voltage & Current Source • An ideal voltage source maintains its stated voltage regardless of the load attached • Independent voltage source • An ideal current source supplies its stated current regardless of the load attached • independent current source I I B B V V A A

32. Ohm’s Law • Some materials are good conductors of electricity, some are poor • In a ‘good’ conductor, the current flowing through the conductor is (approx.) proportional to the voltage across it. • Constant of proportionality is known as resistance, given symbol is R • Ohm’s Law: v(t) = R i(t)

33. i(t) 10 4 V Example