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
Welcome to Networks I
Learning Objectives –



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
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
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
Learning Aids:
Required Text :
 Introduction to Electric Circuits


5th Edition
Dorf and Svoboda
Website :

http:www.engineering.rowan.edu/~jansson/
Check your Email regularly (daily)
Cruise course website
Website :

http:www.engineering.rowan.edu/~jansson/
Learning Evaluation
Grades



Tests (3 @ 20%),
Assignments (40%)
LECTURE:
 In-Class, HW and Participation (20%)

LABS:
 Reports, HW, etc. (20%)
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
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
Imagine a World with..
No internet
No cell phones
No computers
No television or video games
No mass communication (radio,
telephone)
No tall buildings
Imagine a World with..
No
No
No
No




electricity
electronic devices
medical technology
appliances
Refrigerators
Microwaves
Water heaters
Air conditioning
No traffic controls
That world would be
Primitive
Difficult to survive in
A very hard life……
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
Electrical Science Emerges
600 AD
1551
1672
1720
1746
1814
1821
Attractive power of E-S materials
Electricity and Magnetism defined
Pointed Conductors
Grey’s Planetarium
Atmospheric Electricity discovered
Electrical Spectrum detailed
First Electric Motor
Electric Technology
1825
1832
1837
1879
1888
1895
1901
First Electromagnet
First E-M Induction Generator
Telegraph
First DC Power System
First AC Generator
X-rays Discovered
Radio
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
Discovery continues
AC Electric Grids 1900s
Flourescent Lighting 1930s
Computing – 1930s
Television – 1940s
Personal Computing 1970s
Internet – 1990
21st Century ?
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?
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
dq
i
dt
i1   i2
i1
i2
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)
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
dw
v
dq
a
+
vab
-
-
vba
+
vab  vba
b
power
Power is the time rate of expending energy.
Power absorbed by an element is positive,
Power delivered by an element is negative.
i
a
b
i
a
+
vab
-
-
vba
+
dw dw dq
p


vi
dt dq dt
b
passive sign convention (psc)
Positive current flows from positive
voltage to negative voltage.
+
vab
-
i
a
b
i
a
vab
+
b
Is the current in
Is the current in
this resistor positive
this element positive
or negative?
or negative?
power and psc
p=v•i
Power is absorbed by an element adhering to the
passive sign convention (sink)
+ vab i
a
b
Power is supplied by an element not adhering to
the passive sign convention (source)
i
a
vab +
b
power and energy
p=v•i
power = voltage * current

w
0
pdt
t
energy = power * time
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
dq
i
dt
i1   i2
i1
i2
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
dw
v
dq
a
+
vab
-
-
vba
+
vab  vba
b
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
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
power
Power is the rate of expending energy.
Power absorbed by an element is positive,
Power delivered by an element is negative.
i
a
b
i
a
+
vab
-
-
vba
+
dw dw dq
p


vi
dt dq dt
b
passive sign convention (psc)
positive current flows from positive
voltage to negative voltage.
+
vab
-
i
a
b
i
a
vab
+
b
Is the current in
Is the current in
this resistor positive
this element positive
or negative?
or negative?
power and psc
p=v•i
Power is absorbed by an element adhering to the
passive sign convention (sink)
+ vab i
a
b
Power is supplied by an element not adhering to
the passive sign convention (source)
i
a
vab +
b
power and psc example
what is the power absorbed or supplied by
the element below, when i = 4A?
i
a
vab = 12V +
b
power = 12V x 4A = 48 W
does not adhere to passive sign convention,
so power is supplied.
power and psc quiz
what is the power absorbed or supplied by
the element below, when i = 4A?
i
a
vab = 12V +
b
power = 12V x 4A = 48 W
does not adhere to passive sign convention,
so power is supplied.
power and energy
p=v•i
power = voltage * current
power is the time rate of expending energy

w
0
pdt
t
energy = power * time
energy is the capacity to do work
power and energy
energy = force x distance
power = energy / time period (secs)
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
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?
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
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
+
i
a
vab b
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
+
i
a
vab bc
ideal meters
ammeters – negligible voltage drop
through it
voltmeters – negligible current flows
into it
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)
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problem statement
situation and assumptions
goal and requirements
plan  act  verify  if correct, solved
if not, plan  act  verify  iterate as needed
WHAT DO YOU KNOW (or,
what’s going to be on the
test)?
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