NETWORKS 1: 09092010203

1
CHAPTER 1

• 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
• 5th Edition
• Dorf and Svoboda
• Website
• httpwww.engineering.rowan.edu/jansson/
• Check your Email regularly (daily)

5
Cruise course website

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

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Learning Evaluation

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

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Section 1 PC/Laptop Reqmts

• 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

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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

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Imagine a World with..

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

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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 Dianas temple
• 658 AD Japans first magnetic cars

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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

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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

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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

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Discovery continues

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

i1
Resistor
Battery
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

19
units

• Systeme International dUnites
• Base Units (m, kg, s, A, K, mol, cd)
• Derived Units (J, W, C, V, O, S, F, Wb, H)
• See text page 13
• What are base units for Energy (J) and Power (W)

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voltage

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

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power

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

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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?
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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)

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

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
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

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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.

30
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?
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)

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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.

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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.

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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

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power and energy

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

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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

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?

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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

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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

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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

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ideal meters

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

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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

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WHAT DO YOU KNOW (or, whats going to be on the
test)?
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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