26-12-2012, 02:05 PM
08-Mesh Analysis
1Mesh Analysis.pdf (Size: 375.97 KB / Downloads: 31)
Introduction
•Last lecture considered Nodal Analysis
Use KCL at each node
Solve for node voltage
Special treatment (supernode) for voltage sources
•Next consider mesh analysis
Use KVL at each node
Solve for current through meshs
Special treatment (supermesh) for current sources
Mesh Analysis
Steps to solve a circuit with N meshes
1.Assign a mesh current to N meshes
2.Apply KVL to each of the N meshes to generate N equations
3.Use Ohm’s Law to express voltages as functions of mesh currents (may be combined with step 2)
4.Solve resulting simultaneous linear equations
Mesh Analysis with Current Sources
• Presence of current sources reduces the number
of equations (unknowns) mesh analysis
• If current source (independent or dependent)
exists in one loop only
Mesh current = current source
• Two or more supermeshes that intersect can be
combined into a larger supermesh
• Properties of a supermesh
Current source inside the supermesh provides a
constraint equation needed to solve for the
individual mesh currents
A supermesh has no current of its own
A supermesh reduces the number of KVL equations
KCL must be also applied for an additional
independent equation
Nodal and Mesh Analyses by Inspection
• Under certain circumstances we can write nodal
or mesh analysis equations simply by inspecting
the circuit
Saves time
Fewer errors
• Inspection can be used in nodal analysis when all
sources are independent current sources
• Inspection can be used in mesh analysis when all
sources are independent voltage sources
• See text 3.6 for more details
Nodal Versus Mesh Analysis
• Use nodal analysis when network has:
Many parallel connected elements
Many current sources
Supernodes
• Use mesh analysis when network has:
Many series connected elements
Many voltage sources
Supermeshes