Linear Circuits - ECE 2040: Circuit Analysisece2040.ece.gatech.edu/videos/Module1Handouts.pdf ·...
Transcript of Linear Circuits - ECE 2040: Circuit Analysisece2040.ece.gatech.edu/videos/Module1Handouts.pdf ·...
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Linear Circuits
An introduction to electric circuit elements and a study of circuits containing such devices.
Dr. Bonnie H. FerriProfessor and Associate ChairSchool of Electrical and Computer Engineering
School of Electrical and Computer Engineering
Concept Map: Background Module 1
3
Resistive
Circuits
Reactive
CircuitsFrequency
Analysis
Power
BackgroundBackground
Background• Charge
• Current
• Voltage
• Power
• Resistor
• Sources
• Circuits
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Nathan V. ParrishPhD Candidate & Graduate Research AssistantSchool of Electrical and Computer Engineering
School of Electrical and Computer Engineering2
Charge and
Current
•Calculate the force charges exert on one another•Calculate functions of charge and current
� Calculate the forces two point charges exert on each other
� Calculate current based on a charge function� Calculate charge based on a current function
Lesson Objectives
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� Property of matter� Quantized� Measured in Coulombs ( C )
Electric Charge
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Electromagnetic Force
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Reference Directions
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� Discussed charge as a property of matter� Calculated forces of charge using Coulomb’s Law� Explored electric fields – the means of this
interaction� Described current as the time derivative of charge� Emphasized the importance of current reference
directions
Summary
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Nathan V. ParrishPhD Candidate & Graduate Research AssistantSchool of Electrical and Computer Engineering
School of Electrical and Computer Engineering2
Voltage
•Modify voltage values to reflect voltage references•Describe how a chemical battery works•Identify if a battery is charging or discharging
� Calculate voltage from the energy gained/consumed as a charge moves through an electric field
� Correctly specify voltages as references change� Describe the operation of a chemical battery� Identify if a battery is charging or discharging
based on the voltage reference and current flow
Lesson Objectives
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Lead-Acid Batteries - Discharging
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Cathode Anode
Lead-Acid Batteries - Charging
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Anode Cathode
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� Charge crates electric fields� Voltage is energy gained/released as charges
move through an electric field� Described how voltage originates from
differences in charge density� Case study: how lead-acid batteries work
Summary
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Nathan V. ParrishPhD Candidate & Graduate Research AssistantSchool of Electrical and Computer Engineering
School of Electrical and Computer Engineering2
Power and Energy
•Calculate power and energy•Describe the difference between power and energy•Use conservation of energy to find unknown energy•Use power to calculate current or voltage
� Calculate power from energy function� Calculate energy from a power function� Use conservation of energy to find power of an
unknown device� Calculate power from voltage and current� Find a voltage or a current for a device with a
known power
Lesson Objectives
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You run a power company. Do you charge customers for power or energy? Why?
Charging for Power
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Pause
Conservation of Energy
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� Described the relationship between power and energy and how to calculate them
� Described how voltage and current relate to power
� Presented a derivation for conservation of power and how this property is used in analysis
� Solved first simple analysis problem
Summary
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Nathan V. ParrishPhD Candidate & Graduate Research AssistantSchool of Electrical and Computer Engineering
School of Electrical and Computer Engineering2
Introduction to
Circuit Diagrams
•Identify a collection of basic circuit elements•Be able to identify nodes•Identify short/open circuits•Identify equivalent circuit diagrams
� Identify a set of circuit elements� Identify the nodes in a circuit diagram� Recognize self-contradictory circuits� Identify open/closed circuit� Identify when two circuits are equivalent� Modify a circuit to form an equivalent circuit
Lesson Objectives
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Circuit Diagrams
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� Devices are presented with some known parameters
� We wish to identify the behavior of the device
� Identify behavior based on the circuit using calculation
What is Circuit Analysis?
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� Zero internal resistance� Nodes and junctions� Zero voltage drop on node
� Arbitrary current possible
Wires
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Independent Sources
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Independent Voltage
Source
Independent Current
Source
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Dependent Sources
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Dependent Voltage
Source
Dependent Current
Source
Resistors
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� Devices for resisting current� Drawn as zig-zag lines� Number of zigs ands zags can vary� Other similar devices will be
introduced as they are encountered
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Ground
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� Common Point of reference� Path of electrons
� Lightning rod (literal ground)� Prevent electrocution� Prevent damage to sensitive
components
Open/Short Circuits
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Changing Circuits
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� Described the concept of a node and how to identify one� Introduced independent and dependent voltage and current
sources� Introduced a resistor – a device that will be discussed in
more detail later� Presented the idea of a ground� Showed examples of self-contradictory circuits� Described how circuits can be equivalent
Summary
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Dr. Bonnie H. FerriProfessor and Associate ChairSchool of Electrical and Computer Engineering
School of Electrical and Computer Engineering
Module 1
Background
Wrap Up
Summary of Background Module
Concept Map: Background Module 1
3
Resistive
Circuits
Reactive
CircuitsFrequency
Analysis
Power
BackgroundBackground
Background• Charge
• Current
• Voltage
• Power
• Resistor
• Sources
• Circuits
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� Understand charge and current� Be able to calculate the effect of one charge on
other charges
� Be able to calculate current from charge flow in time
Important Concepts and Skills
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� Understand how voltage is created by differences in charge density
� Understand how chemical reactions can cause a voltage
� Be able to use voltage references
� Be able to identify some basic circuit elements� Be able to identify nodes of a circuit diagram
� Be able to identify open/short circuits
� Be able to move elements of a diagram
Important Concepts and Skills
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� Be Able to calculate power from energy� Be able to analyze circuit using conservation of power
� Be able to analyze circuit using power, voltage, and current