ECEn 301: Fundamentals of
Electrical Engineering
Prof. David Long
An Introduction
• Dr. David G. Long
• At BYU for over 20 years
• Professor of Electrical & Computer Engineering
• Director, BYU Center for Remote Sensing
• Previously at NASA’s Jet Propulsion Lab
• Remote sensing radar systems
• NSCAT, SeaWinds, SIR-C, Magellan flight projects
• Member of several NASA Science Teams
A Dog & Pony Show
‘Iota Jump for Joy’ &
‘Tethered Tempest’
‘Tethered Tempest’
‘Micro Mu’ &
‘Muttly’
(actually these are miniature horses
rather than ponies)
“Tethered tempest”
at two months
Small and Simple
Alma 37:6
6 Now ye may suppose that this is foolishness in me;
but behold I say unto you, that by small and simple
things are great things brought to pass; and small
means in many instances doth confound the wise.
ECEN 301
Discussion #1 – Fundamentals
4
General Schedule…
• Mondays and Wednesdays: Professor lecture
• Slides: http://ece301web.groups.et.byu.net/
• Question answering in class
• Fridays: RA Recitation (quizes, review,
question answering)
• Mondays or Thursdays, depending on section:
Laboratory (staff)
• Hands-on experience
ECEN 301
Discussion #1 – Fundamentals
5
Electrical Engineering
• You are going to work with Electrical
Engineering during your career – you need to
know about it.
• What do Electrical Engineers do?
• Anything electronic or electrical
•
•
•
•
Power
Computers
Control systems
Communications
Engineers and the Space Program
• No such thing as a “Rocket Scientist”
• Rocket Engineers
• Engineers solve problems and make
things work, create new things
• The space program is Engineering
• Solving engineering problems for the space
program helps us solve problems on Earth
Electrical & Computer Engineering
• EE’s and CompE’s do:
• Computers
• Hardware (design)
• Software (program)
• Solve problems
• For us computers are
design & analysis
tools
Electrical & Computer Engineering
• EE’s and CompE’s do:
• Electronics
• Integrated Circuits
Career
Electrical & Computer Engineering
• EE’s and CompE’s do:
•
•
•
•
Radar
Satellite systems
System Engineering
Wireless
Electrical Engineering
• EE’s and CompE’s do:
• Signal processing (TV, telephones, CD-players)
Electrical & Computer Engineering
• EE’s and CompE’s do:
•
•
•
•
Electrical power systems
Power plants
Control systems
Lighting
Electrical & Computer Engineering
• EE’s and CompE’s do:
•
•
•
•
•
•
Communications
Wireless
Cellular phones
Satellites
Radio/TV
HDTV
Electrical & Computer Engineering
• EE’s and CompE’s do:
•
•
•
•
Technical sales
Law
Biotechnology
Management
TRANSPORTATION W/OUT ECE
HOUSING WITHOUT ECE
Lighting
Air Conditioning
ENTERTAINMENT WITHOUT ECE
HEALTH CARE WITHOUT ECE
BUSINESS WITHOUT ECE
Lecture 1 – Fundamentals of
Electrical Circuits
ECEN 301
Discussion #1 – Fundamentals
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Important Concepts
• Ideal/Dependent voltage sources
• Ideal/Dependent current sources
• Electrical Networks
•
•
•
•
Branches
Nodes
Loops
Meshes
ECEN 301
Discussion #1 – Fundamentals
21
Ideal Voltage Sources
• An electric device that generates a prescribed
voltage
• Provides a prescribed voltage across its
terminals irrespective of the current flowing
through it. The amount of current supplied by
the source is determined by the circuit
connected to it
ECEN 301
Discussion #1 – Fundamentals
22
Ideal Voltage Sources
• Time-dependent voltage source
• Voltage as a function of time t
• Lowercase v usually connotes AC source
i
+
vs(t)
+
_
vs(t)
Circuit
_
ECEN 301
Discussion #1 – Fundamentals
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Ideal Voltage Sources
• Time-dependent voltage source – special case:
sinusoidal
• Voltage as a function of time t
• IE: vs(t) = Vcos(ωt)
• Lowercase v usually connotes AC source
i
+
vs(t)
+
~_
vs(t)
Circuit
_
ECEN 301
Discussion #1 – Fundamentals
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Ideal Voltage Sources
• DC voltage source
• Voltage is not a function of time
• Capital V connotes DC voltage
• DC voltage source example: a battery
i
+
A generic voltage is denoted
by just a lowercase v
+
v
Vs
_
ECEN 301
Circuit
_
Discussion #1 – Fundamentals
25
Ideal Voltage Sources
• Source-load representation
i
i
+
+
+ Battery
ECEN 301
Light
Vs
+
_
v
R
_
Discussion #1 – Fundamentals
Source
v
Load
_
26
Ideal Current Sources
• An electric device that generates a prescribed
current
• Provides a prescribed current to any circuit
connected to it. The voltage generated by the
source is determined by the circuit connected to
it.
ECEN 301
Discussion #1 – Fundamentals
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Ideal Current Sources
• Lowercase i connotes AC current
• Capital I connotes DC current
is, Is
+
is,Is
vs
Circuit
_
ECEN 301
Discussion #1 – Fundamentals
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Dependent (Controlled) Sources
• Diamond shaped source indicates dependent source
• Dependent sources are an important part of amplifiers
Source Type
vs
+
_
ECEN 301
is
Relationship
Voltage controlled voltage source (VCVS)
vs = avx
Current controlled voltage source (CCVS)
vs = aix
Voltage controlled current source (VCCS)
is = avx
Current controlled current source (CCCS)
is = aix
Discussion #1 – Fundamentals
29
Electrical Network
• A collection of elements through which current
flows
R1
+
_
R2
Vs1
R4
+
_
R3
ECEN 301
Vs2
Discussion #1 – Fundamentals
R5
30
Electrical Network - Branches
• Any portion of a circuit with two terminals connected
to it.
• May consist of one or more circuit elements
R1
+
Branch v
voltage
Branch
current
+
_
R2
Vs1
_
ECEN 301
i
Vs2
R4
+
_
R3
Discussion #1 – Fundamentals
R5
31
Electrical Network - Branches
• Any portion of a circuit with two terminals connected
to it.
• May consist of one or more circuit elements
R1
+
Branch v
voltage
Branch
current
+
_
R2
Vs1
_
ECEN 301
i
Vs2
R4
+
_
R3
Discussion #1 – Fundamentals
R5
32
Electrical Network - Nodes
• The junction of two or more branches
• Trivial Node: the junction of only two branches
R1
Node
+
_
R2
Vs1
R4
+
_
R3
ECEN 301
Vs2
Discussion #1 – Fundamentals
R5
33
Electrical Network - Nodes
• The junction of two or more branches
• Trivial Node: the junction of only two branches
Node a
Node
Node b
R1
+
_
R2
Vs1
Vs2
R4
+
_
R3
R5
Node c
ECEN 301
Discussion #1 – Fundamentals
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Electrical Network – Supernodes
• Obtained by defining a region that encloses more than
one node
• Can be treated the exact same way as normal nodes
R1
Supernode
+
_
R2
Vs1
R4
+
_
R3
ECEN 301
Vs2
Discussion #1 – Fundamentals
R5
35
Electrical Network – Loops
• Any enclosed connection of branches
R1
+
_
R2
Vs1
R4
+
_
R3
ECEN 301
Vs2
Discussion #1 – Fundamentals
R5
36
Electrical Network – Meshes
• A loop that does not contain other loops
R1
+
_
R2
Vs1
R4
+
_
R3
ECEN 301
Vs2
Discussion #1 – Fundamentals
R5
37