INC 112 Basic Circuit Analysis Lecturer Assistant Prof. Dr. Poj Tangamchit.
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Transcript of INC 112 Basic Circuit Analysis Lecturer Assistant Prof. Dr. Poj Tangamchit.
INC 112 Basic Circuit Analysis
Lecturer
Assistant Prof. Dr. Poj Tangamchit
About the Instructor
Office: CB40603 (CB4 6th floor)Control System and Instrumentation Eng. (INC)
Tel: x-9094
E-mail: [email protected]
Research Interest: Robotics, Artificial Intelligence (AI)
Lecture: Self-lecture. Reading material before coming to class is encouraged.
Freshmen’s Requirements
• Computer INC160
• Software INC151
• Circuit INC112
Course Details
• 3 Credits
• Class time 3 hours / week
• Review + Homework 6 hours/week
• E-learning material (DVD) is provided
Scoring & Grading
Midterm Exam 35%Final Exam 35%Homework, assignment 20%Quiz (Pop quiz) 10%
Grading follows the faculty of Engineering’sstandard procedure.
Homework & Quiz
Homework takes time.Allocate 6-12 hours each week for it.
Students need self-study outside class time.
Assignment
Course Webpage
http://www.inc.eng.kmutt.ac.th/inc112
• Lecture Slides• Homework• Homework/ Quiz Solutions• Announcements
Textbook
Engineering Circuit Analysis,7th edition McGrawHillWilliam H. Hayt Jr.,Jack E. Kemmerly,Steven M. Durbin
How to read a Textbook
Book Overview• Read Index• Think about what should be in each chapter• Think about what each chapter relate to each other
Chapter Focus• Read the title of each section, Guess what it will say• Look at pictures and description• Read equations and Math parts• Reread the section that you want to know more
Electricity
Electricity is a result from the flow of electrons.
= electron
electricity
Note: Electricity flows in the opposite directionof electron flow.
Electric Current vs. Electron Current
+ +- -= Atom Structure
+ +- -+ +- -
+ +- -+ +
--
+ +electricity
MetaphorElectricity is similar to water flow.
Water flows from high levelto low level.
Electricity flows fromhigh voltage to low voltage.
HighVoltage
LowVoltage
Measurement of ElectricitySince we use electricity to do work for us, howCan we measure its energy?
How can we measure the water power?Think about a water gun.
• strong (fast, high kinetic energy)• amount of water
• Voltage• Current
HighVoltage
LowVoltage
Imagine the water power at the outlet
Electric Potential (ศกยไฟฟา) Which water drop has more impact force at the ground?
Potential Energy (Height)
transform
Kinetic Energy (Velocity)
Electric potential can be compared with the height of the water drop from the reference ground
Ground: Reference PointNormally, we measure height compared to the sea level.
Also, electric potential at a point can be measured compared to the electric potential at the ground.
Unit: Volt (V)
Electric potential,or voltage has a unit “volt”.
Ground always has 0 volts.
Voltage (ความตางศกย)Voltage is a difference of electric potential between 2 points
Unit: Volt
Compare to the height of 2 water drops
Electric Current (กระแส)
Low current High current
Electric Current Unit
Unit: Ampere, Amp (A)
Note: Both current and voltage have directions
What is Circuit Analysis about?
To calculate voltage or current at some points
and some time in electric circuits
Course Overview
Constant voltage
Constant current
Mid
termRules:Ohm’s lawKirchoff’s law
Techniques:Mesh AnalysisNode AnalysisSuperpositionThevenin/ Norton
Circuits
Time
Voltage
Current
Voltage
Current
DC (Direct current) AC (Alternating current)
Frequency
Transient Response
Phasor Concept
Topics
Week 1: Introduction to Electricity, Simple DC circuits, Ohm’s lawWeek 2: Kirchoff’s voltage law, Kirchoff’s current lawWeek 3: Nodal AnalysisWeek 4: Mesh AnalysisWeek 5: Thevenin’s theoremWeek 6: Norton’s theorem, Maximum power transfer theoremWeek 7: Introduction to AC circuits and components
Week 8: Midterm ExamWeek 9: Transient response of RL circuitsWeek 10: Transient response of RC circuitsWeek 11: Transient response of RLC circuitsWeek 12: Phasor conceptWeek 13: Phasor circuit analysisWeek 14: AC Power, Frequency response
Week 15: Final Exam
Components
• Electric sources• Independent Sources – voltage, current• Dependent Sources – voltage, current
• Resistors• Measurement Devices
• Ammeters: measure current• Voltmeters: measure voltage
• Ground – reference point• Electric Wire
1V 1A1Ω
IndependentVoltageSource
IndependentCurrentSource
Resistor Ground
Symbol
Electric wire
General Rules
• All points on a same electric wire have the same voltage.
• A voltage source always have voltage difference of its pins equal to its value.
• A current source always have current pass through it equal to its value.
• Ground always has zero voltage. (0 volts)
Electric Flow Rule• Electric current flows from high voltage to low voltage when there is a path.
• Electric current can freely pass through electric wire.
• Electric current can flow through a resistor with the amount according to Ohm’s law.
• Electric current can flow through a voltage source with the amount depended on other components in the circuit.
• Electric current can flow pass a current source according to its value.
Three Measurementsof Electricity
Voltage Volt (V)
Current Ampere (A)
Resistance Ohm (Ω)
Prefix
Giga (G) 109
Mega (M) 106
Kilo (K) 103
Centi (c) 10-2
Milli (m) 10-3
Micro (μ) 10-6
Nano (n) 10-9
Pico (p) 10-12
Simple DC Circuit
1V 1Ω
Current
Metaphor
1V 1Ω
Current
Increasing V is compared to ?Increasing R is compared to ?
Ohm’s Law
V = IR
Voltage (Volts) = current (Amperes) x resistance (Ohms)
2A
x voltsx+4 volts2Ω
for using with a resistor only
Note: Electric wire has a resistance of 0 ohms
Electric Current
1V 1Ω
1A
1A
1A
Every point in the circuit has current = 1A
Electric Voltage
1V 1Ω
x + 1 Volts
x Volts
Ground
Ground = reference point always have voltage = 0 volts
1V 1Ω
1 Volts
0 Volts
1V 1Ω
Electric Voltage (2)
1 Volts
0 Volts
0 Volts
1V 1Ω
Electric Voltage (3)
1 Volts
0 Volts
1 Volts
1 Volts
Negative Voltage and Current
+
2 volts
-
-
-2 volts
+
Same as
Same as
1 A -1 A
PowerSymbol P has a unit of Watt
P = VI
+
V
-
I
Absorb power
-
V
+
I
Generate power
Passive Sign Convention
Absorb power: Power has a sign +
Generate power: Power has a sign -
Example
10V 4KΩ
2.5mA
DC source generates power = 10V * -2.5mA = - 25mW
Resistor absorbs power = 10V * 2.5mA = 25mW
Note: Resistors always absorb power but DC source caneither generate or absorb power
Direction of Voltage & Current on Resistors
+ -
Resistor always absorb power.Therefore, it always have current flow through it fromhigh voltage pin to low voltage pin.
- +or