NETWORKS 1: 090920101

1
CHAPTER 1

• NETWORKS 1 0909201-01
• 6 SEPTEMBER 2005
• ROWAN UNIVERSITY
• College of Engineering
• Dr Peter Mark Jansson, PP PE
• DEPARTMENT OF ELECTRICAL COMPUTER ENGINEERING
• Autumn Semester 2005 - Quarter One

2
Welcome to Networks I

• Learning Objectives
• Define circuit elements
• Master Ohms Law, Kirchoffs Laws, etc.
• 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 and
  MatLab

3
Learning Aids Overview

• Lectures Rowan 104
• Laboratories Rowan Hall Room 204/6 - 221
• One Lab Section Thurs 3.15-6.00 pm
• Syllabus/Text (read ahead ch. 1/2)
• Computer Tools
• Learning Checks
• Website
• Email

4
Learning Check 1

• List 2 learning objectives of the course
  Networks 1

5
Learning Aids

• Required Text
• Introduction to Electric Circuits
• 6th Edition
• Dorf and Svoboda
• Website
• httpwww.users.rowan.edu/jansson/
• Check your Email regularly (daily)

6
Cruise course website

• Website
• httpwww.engineering.rowan.edu/jansson/

7
Learning Check 2

• List the 2 learning aids of the course Networks
  1 that you think you will find most helpful to
  you

8
Learning Evaluation

• Grades
• Tests (3 _at_ 20) 60,
• Assignments (40)
• LECTURE
• In-Class LCs, HW and Participation (20)
• LABS
• Reports, HW, etc. (20)

9
How do we learn?

• hearing
• seeing
• reading
• doing
• other?
• Do you think you can learn most everyones name
  (15) in this room in lt10 minutes?
• Lets Experiment.

10
Lets stand up.

• put down your pencils .
• for the name game
• NOTE Very important learning aid is each other

11
Learning Check 3

• List 3 names of colleagues that you did not know
  before today

12
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

13
Imagine a World with..

• No internet
• No cell phones
• No computers
• No television or video games
• No mass communication (radio, telephone)
• No tall buildings

14
Imagine a World with..

• No electricity
• No electronic devices
• No medical technology
• No appliances
• Refrigerators
• Microwaves
• Water heaters
• Air conditioning
• No traffic controls

15
That world would be

• Primitive
• Difficult to survive in
• A very hard life

16
Learning Check 4

• List 2 important electric technologies that have
  improved the quality of life for human beings on
  Earth

17
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 Dianas temple
• 658 AD Japans first magnetic cars

18
Electrical Science Emerges

• 600 AD Attractive power of E-S materials
• 1551 Electricity and Magnetism defined
• 1672 Pointed Conductors
• 1720 Greys Planetarium
• 1746 Atmospheric Electricity discovered
• 1814 Electrical Spectrum detailed
• 1821 First Electric Motor

19
Electric Technology

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

20
Quotable Quotes

• Heavier than air flying machines are impossible
• Lord Kelvin Royal Society 1895
• There is no likelihood man can ever tap the power
  of the atom
• Robert Milliken Nobel Laureate Physics 1923

21
Discovery continues

• AC Electric Grids - 1900s
• Flourescent Lighting - 1930s
• Computing 1930s
• Television 1940s
• Personal Computing - 1970s
• Internet 1990
• 21st Century ?

22
Learning Check 5

• Of the electrical discoveries described in the
  last 3 slides, which was the most significant in
  terms of impact on modern human society?

23
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

i1
Resistor
Battery
Where is ground?
24
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

25
units

• Systeme International dUnites
• Base Units (m, kg, s, A, K, mol, cd)
• Derived Units (J, W, C, V, O, S, F, Wb, H)
• What are base units for Energy (J) and Power (W)

26
voltage

• The voltage across an element is the work
  (energy) required to move a unit positive charge
  from the - terminal to the terminal.

27
power

• Power is the time rate of expending energy.
• Power absorbed by an element is positive, Power
  delivered by an element is negative.

28
Learning Check 6

• If 6V (volts) is dissipated across a resistor in
  which the current is 2A (amperes) what is the
  power used in watts?

29
passive sign convention (psc)

• positive current flows from positive voltage to
  negative voltage.

Is the current in this resistor positive or
negative?
Is the current in this element positive or
negative?
30
Learning Check 7

• PSC positive current flows from positive
  voltage to negative voltage.

If i is positive, does this conform with PSC?
If i is positive, does this conform with PSC?
31
passive sign convention (psc)

• positive current flows from positive voltage to
  negative voltage.

Is the current in this resistor positive or
negative?
Is the current in this element positive or
negative?
32
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)

33
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.

34
power and psc quiz

• what is the power absorbed or supplied by the
  element below, when i -2A?
• power -12V x -2A 24 W
• does adhere to passive sign convention,
• so power is absorbed.

35
power and energy

• p v i
• power voltage current (units watts)
• power is the time rate of expending energy
• energy power time (units Joules w-s)
• energy is the capacity to do work

36
power and energy

• energy force x distance
• power energy / time period (secs)

37
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/secWatts)
• power 30J/10-2 sec 3000W 3kW

38
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?

39
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

40
Learning Check 8

• your iPod shuffle uses a small 3.7V polymer
  lithium battery with stored energy of 11,322
  joules. How many hours will it play tunes if it
  draws 70.81mA current when in operation?

41
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

42
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

43
ideal meters

• ammeters negligible voltage drop through it
• voltmeters negligible current flows into it

44
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

45
Homework for next Tuesday

• See website for Assignment 1
• show all work for any credit
• Dorf Svoboda, pp. 22-27, pp. 52-56
• Begin Lab HW Assignment 1