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Lecture 4:Nodal AnalysisNilsson & Riedel 4.1-4.4

ENG17 (Sec. 2): Circuits I

Spring 2014

April 10, 2014

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Overview

• Recap on Voltage & Current Dividers

• Term Definition• Node Voltage Method• NVM w/Dependent

Sources• NVM Special Cases

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Voltage Divider

• Wheatstone Bridge– 2 voltage dividers in parallel

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Current Divider

• Similar analysis

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Overview

• Recap on Voltage & Current Dividers

• Term Definition• Node Voltage Method• NVM w/Dependent

Sources• NVM Special Cases

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Planar Circuit

Planar Not Planar

Nodal good for eitherMesh good for planar

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Identify

• Node• Essential Node• Path• Branch• Essential Branch• Loop• Mesh

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Simultaneous Equations

• How many unknown currents? • How many equations needed?

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Overview

• Recap on Voltage & Current Dividers

• Term Definition• Node Voltage Method• NVM w/Dependent

Sources• NVM Special Cases

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Node Voltage Method – Setting Up

• Identify essential nodes• Define reference node• Apply KCL to each non-reference node,

express current in terms of node voltages• Solve simultaneous equations

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Node Equations

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Example

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Overview

• Recap on Voltage & Current Dividers

• Term Definition• Node Voltage Method• NVM w/Dependent

Sources• NVM Special Cases

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Dependent Sources

• Only need to add equation to describe relationship of the dependent source

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Example

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Overview

• Recap on Voltage & Current Dividers

• Term Definition• Node Voltage Method• NVM w/Dependent

Sources• NVM Special Cases

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Source Between Essential Nodes

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w/Dependent Source

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Supernode

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Example

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Recap

• Recap on Voltage & Current Dividers

• Term Definition• Node Voltage Method• NVM w/Dependent

Sources• NVM Special Cases