1. CHAPTER 1 CHAPTER 1 NETWORKS 1: 0909201-02/03 NETWORKS 1: 0909201-02/03 23 OCTOBER 2002 ROWAN UNIVERSITY College of Engineering Professor Peter Mark Jansson, PP PE DEPARTMENT OF ELECTRICAL & COMPUTER ENGINEERING Autumn Semester 2002 – Quarter Two

2. Welcome to Networks I Learning Objectives – Define circuit elements Analyze electrical circuits Apply circuit parameters (v, i, r, p, etc.) Analyze DC circuits with passive elements including: resistance, energy storage (C,L) Build/Model circuits using Mentorgraphics, Pspice, IMITS and MatLab

3. Learning Aids: Overview Lectures – Rowan Auditorium Laboratories – Rowan Hall Room 204/6 Two Lab Sections – M12.30-3.15, M3.30-6.15 Syllabus / Text (read ahead – ch. 1/2) Computer Tools Website Email

4. Learning Aids: Required Text : Introduction to Electric Circuits 5 th Edition Dorf and Svoboda Website : http:www.engineering.rowan.edu/~jansson/ Check your Email regularly (daily)

5. Cruise course website Website : http:www.engineering.rowan.edu/~jansson/

6. Learning Evaluation Grades Tests (3 @ 20%), Assignments (40%) LECTURE:  In-Class, HW and Participation (20%) LABS:  Reports, HW, etc. (20%)

7. Section 1 – PC/Laptop Reqm’ts Windows 9x, NT, 2000, Me or XP Pentium 233 MHz or faster 16 Mb RAM 255 Mb free disk space (required) 12X CD-ROM drive or better 16-bit Sound card or better 2 Mb Video card or better

8. chapter 1 – overview history of electricity electric circuits and current flow systems of units voltage power and energy voltmeters and ammeters circuit analysis and design

9. Imagine a World with.. No internet No cell phones No computers No television or video games No mass communication (radio, telephone) No tall buildings

10. Imagine a World with.. No electricity No electronic devices No medical technology No appliances Refrigerators Microwaves Water heaters Air conditioning No traffic controls

11. That world would be Primitive Difficult to survive in A very hard life……

12. Electrical Engineers Transformed Society Long, long ago in countries far, far away the journey began….. 2367 BC – Hoang-Ti in China 1110 BC – Tchi-nan designed 600 BC – Etruscans control lightning 250 BC – Flying Cupid in Diana’s temple 658 AD – Japan’s first magnetic cars

13. Electrical Science Emerges 600 AD Attractive power of E-S materials 1551Electricity and Magnetism defined 1672Pointed Conductors 1720Grey’s Planetarium 1746 Atmospheric Electricity discovered 1814Electrical Spectrum detailed 1821First Electric Motor

14. Electric Technology 1825First Electromagnet 1832First E-M Induction Generator 1837Telegraph 1879First DC Power System 1888First AC Generator 1895X-rays Discovered 1901Radio

15. Quotable Quotes Everything that can be invented has been invented Charles H. Duell - US Patent Office 1899 Heavier than air flying machines are impossible Lord Kelvin – Royal Society 1895 There is no likelihood man can ever tapthe power of the atom Robert Milliken Nobel Laureate Physics 1923

16. Discovery continues AC Electric Grids 1900s Flourescent Lighting 1930s Computing – 1930s Television – 1940s Personal Computing 1970s Internet – 1990 21 st Century ?

17. electric circuits & current flow An electric circuit is an interconnection of circuit elements linked together to form a closed path so that electric current may flow continuously Battery Resistor i1i1 Where is ground?

18. electric circuits & current flow Current is the time rate of flow of electric charge (q) past a given point Use lower case to indicate a time varying current and upper case to indicate a constant or direct current i1i1 i2i2

19. units Systeme International d’Unites Base Units (m, kg, s, A, K, mol, cd) Derived Units (J, W, C, V, Ω, S, F, Wb, H) See text page 13 What are base units for Energy (J) and Power (W)

20. voltage The voltage across an element is the work (energy) required to move a unit positive charge from the - terminal to the + terminal. a b b a + v ab - - v ba +

21. power Power is the time rate of expending energy. Power absorbed by an element is positive, Power delivered by an element is negative. a b b a + v ab - - v ba + i i

22. passive sign convention (psc) Positive current flows from positive voltage to negative voltage. a b - v ab + i b a + v ab - i Is the current in this resistor positive or negative? Is the current in this element positive or negative?

23. power and psc p = v i Power is absorbed by an element adhering to the passive sign convention (sink) Power is supplied by an element not adhering to the passive sign convention (source) a b + v ab - i a b - v ab + i

24. power and energy p = v i power = voltage * current energy = power * time

25. electric circuits & current flow Current is the time rate of flow of electric charge (q) past a given point Use lower case to indicate a time varying current and upper case to indicate a constant or direct current i1i1 i2i2

26. voltage The voltage across an element is the work (energy) required to move a unit positive charge from the - terminal to the + terminal. a b b a + v ab - - v ba +

27. voltage / current analogy mechanical system analogy: pump, fluid pressure (head), velocity battery, voltage, current high pressure (head)  high voltage increased fluid flow  high current increasing either: increases power

28. circuit analogy envision a closed system of water flowing in troughs pumps elevate the head of the flow and increase its velocity in various troughs flow of mass is conserved energy can be added (pumps) or extracted (waterwheels) though overall system of water flow is conserved energy is transferred by head and velocity in a given part of circuit flowrate is constant

29. power Power is the rate of expending energy. Power absorbed by an element is positive, Power delivered by an element is negative. a b b a + v ab - - v ba + i i

30. passive sign convention (psc) positive current flows from positive voltage to negative voltage. a b - v ab + i b a + v ab - i Is the current in this resistor positive or negative? Is the current in this element positive or negative?

31. power and psc p = v i Power is absorbed by an element adhering to the passive sign convention (sink) Power is supplied by an element not adhering to the passive sign convention (source) a b + v ab - i a b - v ab + i

32. power and psc example what is the power absorbed or supplied by the element below, when i = 4A? power = 12V x 4A = 48 W does not adhere to passive sign convention, so power is supplied. a b - v ab = 12V + i

33. power and psc quiz what is the power absorbed or supplied by the element below, when i = 4A? power = 12V x 4A = 48 W does not adhere to passive sign convention, so power is supplied. a b - v ab = 12V + i

34. power and energy p = v i power = voltage * current power is the time rate of expending energy energy = power * time energy is the capacity to do work

35. power and energy energy = force x distance power = energy / time period (secs)

36. power and energy example a mass of 300 grams experiences a force of 200 newtons. Find the energy (or work expended) if the mass moves 15 cm. Also find the power if the move is completed in 10 milliseconds. energy = force x distance (N m) energy = 200 x.15 = 30J power = energy / second (J/sec=Watts) power = 30J/10 -2 sec = 3000W = 3kW

37. power and energy quiz a Motorola StarTAC cellular phone uses a small 3.6V lithium ion battery with nominal stored energy of 200 joules. For how long will it power the phone if it draws a 3-mA current when in operation?

38. quiz solution 200 joules = 200 watt-secs 3.6 V x 3 mA = 1.08 x 10 -2 watts 200 watt-secs / 1.08 x 10 -2 watts = 18,519 seconds 18,519 seconds / 3600 sec/hr = 5.1 hours

39. voltmeters and ammeters dc current and voltage measurements are made with (analog or digital type) ammeters and voltmeters voltage measurements are made with red probe (+) at point a, and black probe (-) at point b a b + v ab - i

40. voltmeters and ammeters current measurements require breaking into the circuit so the ammeter is in series with the current flow made with red probe (+) at point b, and black probe (-) at point c a b  c + v ab - i

41. ideal meters ammeters – negligible voltage drop through it voltmeters – negligible current flows into it

42. circuit analysis and design analysis – concerned with the methodological study of a circuit to determine direction and magnitude of one or more circuit variables (V, A) problem statement situation and assumptions goal and requirements plan  act  verify  if correct, solved if not, plan  act  verify  iterate as needed

43. WHAT DO YOU KNOW (or, what’s going to be on the test)?

44. Homework for next week See website show all work for any credit Dorf & Svoboda, pp. 24-27 Problems 1.3-1, 1.3-2, 1.3-6, 1.3-7, 1.6-3, 1.6-5, 1.6-10, 1.6-12, 1.6-14, 1.6-19 Verification Problem 1-1 Design Problem 1-2