Lecture 5: Mesh-Current & Source Transformations Nilsson & Riedel 4.5-4.9

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Lecture 5:Mesh-Current & Source TransformationsNilsson & Riedel 4.5-4.9

ENG17 (Sec. 2): Circuits I

Spring 2014

April 15, 2014

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Overview

• Mesh-Currents• Mesh-Current

w/Dependent Source• Special Cases• Node-Voltage vs.

Mesh-Current• Source

Transformations

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Go Mesh or Go Home

• Mesh = loop with no other loops inside it

• Mesh-Current Method needs [be – (ne – 1)] equations

• Planar circuits only• Mesh current = current that exist only in

the perimeter of a mesh• Mesh current ≠ Branch current

– maybe

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Mesh Currents

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Strategy for Mesh-Current Analysis

1. Assign mesh currents.

2. Apply KVL to each mesh.– Use Ohm’s law to express voltages in terms

of mesh currents

3. Solve the resulting simultaneous equations to get mesh currents.

4. Use mesh currents to find branch currents and/or any other parameter.

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EvolutionBranch Currents

Mesh Currents

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Example

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Overview




Transformations

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(Don’t) Mesh It Up

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Overview




Transformations

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Mesh with Current Source

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Supermesh…Super Cool

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Example

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Overview




Transformations

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Node…Mesh…and all the rest

• Why are we here?• Difficult answer• Try to make life easier• Supernodes or supermeshes?

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Comparison

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Overview




Transformations

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Source Transformations

• Akin to series / parallel reductions and delta-to-wye transformation

• Allows a voltage source with resistor in series to be replaced by current source in parallel with same resistor

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Example

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Additional Elements

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Example

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Recap




Transformations

Lecture 5: Mesh-Current & Source Transformations Nilsson & Riedel 4.5-4.9

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Transcript of Lecture 5: Mesh-Current & Source Transformations Nilsson & Riedel 4.5-4.9