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CIRCUITS by Ulaby & MaharbizAll rights reserved. Do not reproduce or distribute.
© 2013 National Technology and Science Press
REVIEW OF LECTURES 01-04REVIEW OF LECTURES 01 04
06/27/2013 ECE225 CIRCUIT ANALYSIS
Summary of Chapter 1y p
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Units, Multiples, NotationAll rights reserved. Do not reproduce or distribute. © 2013 National Technology and Science Press
, p ,
Charge & CurrentAll rights reserved. Do not reproduce or distribute. © 2013 National Technology and Science Press
g
Unit of charge = coulombg
Voltage & PowerAll rights reserved. Do not reproduce or distribute. © 2013 National Technology and Science Press
g
PowerAll rights reserved. Do not reproduce or distribute. © 2013 National Technology and Science Press
Rate of expending or absorbing energyp g g gy
ddd vidtdq
dqdw
dtdwP
Energy conservation
0P
Units: wattsUnits: wattsOne watt = power rate of one joule of work per second. 1 W = 1 A x 1 V
Passive Sign Conventiong
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Summary of Chapter 2All rights reserved. Do not reproduce or distribute. © 2013 National Technology and Science Press
y p
Ohm’s Law
Voltage across resistor is proportional to currentVoltage across resistor is proportional to current
iR
iR
Resistance: ability to resist flow of electric current
resistivity
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Kirchhoff’s Current Law (KCL)( )
Sum of currents entering a node is zeroSum of currents entering a node is zeroAlso holds for closed boundary
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Kirchhoff’s Voltage Law (KVL)All rights reserved. Do not reproduce or distribute. © 2013 National Technology and Science Press
g ( )
Sum of voltages around a closed path is zeroSum of voltages around a closed path is zeroSum of voltage drops = sum of voltage rises
Resistors in SeriesAll rights reserved. Do not reproduce or distribute. © 2013 National Technology and Science Press
Equivalent resistance (series) is sum of resistances
Voltage divided over resistors (voltage divider)
Resistors in ParallelAll rights reserved. Do not reproduce or distribute. © 2013 National Technology and Science Press
Source TransformationAll rights reserved. Do not reproduce or distribute. © 2013 National Technology and Science Press
Hence,
For the two circuits to be equivalent :
R1,R2,R3=Delta
R3,R4,R5=Delta
R1,R3,R4=Y
R2,R3,R5=Y
Circuit with no two resistors sharing the same current or same voltage
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All rights reserved. Do not reproduce or distribute. © 2013 National Technology and Science Press
Hence,
( Assuming no connection at node 3)
Simultaneous solution leads to:
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Summary of Chapter 3 (Parts 1 & 2)y p ( )
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Node-Voltage Methodg
Node 1
Node 2Node 3
Node 2
Node 3
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Node-Voltage Methodg
Three equations in 3 unknowns:Solve using Cramer’s rule, matrixinversion or MATLABinversion, or MATLAB
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Mesh-Current MethodAll rights reserved. Do not reproduce or distribute. © 2013 National Technology and Science Press
Two equations in 2 unknowns:Solve using Cramer’s rule, matrixinversion, or MATLAB
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Mesh-Current Method
Mesh 1But
Mesh 2Hence
Mesh 3
Nodal Analysis by Inspectiony y p
Requirement: All sources are independent current sources Requirement: All sources are independent current sources
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Mesh by InspectionAll rights reserved. Do not reproduce or distribute. © 2013 National Technology and Science Press
y pRequirement: All sources are independent voltage sources