Nt1310 Unit 4

FHFHGFKYITJ;LKJHGFKFDLKJDSLKJHGFD.JKHGFDDRFRYRHFYHFDGCVGDVXVBVGDVMotivation
3.2 Nodal analysis.
3.3 Nodal analysis with voltage sources.
3.4 Mesh analysis.
3.5 Mesh analysis with current sources.
3.6 Nodal and mesh analysis by inspection.
3.7 Nodal versus mesh analysis.
Circuit Analysis I 2
3.1 Motivation (1)
If you are given the following circuit, how can we determine (1) the voltage across each resistor, (2) current through each resistor. (3) power generated by each current source, etc.
What are the things which we need to know in order to determine the answers?
Circuit Analysis I 3

3.1 Motivation (2)
Things we need to know in solving any resistive circuit with current and voltage sources only:
• Kirchhoff’s Current Laws
Select a node as the reference node.
2. Assign voltages v1,v2,...,vn-1 to the remaining n-1 nodes. The voltages are referenced with respect to the reference node.
3. Apply KCL to each of the n-1 non-reference nodes. Use Ohm’s law to express the branch currents in terms of node voltages.
4. Solve the resulting simultaneous equations to obtain the unknown node voltages.
Circuit Analysis I 6

3.2 Nodal Analysis (3)
Example 2 – circuit independent current source only
Apply KCl at node 1 and
A super-mesh has no current of its own.
3. A super-mesh requires the application of both KVL and KCL.
Circuit Analysis I 18

3.6 Nodal and Mesh Analysis with Inspection (2)
Example 10 – By inspection, write the nodal voltage equations for the circuit
*Refer to in-class illustration, textbook
Circuit Analysis I 19
3.6 Nodal and Mesh Analysis with Inspection (3)
Example 11 – By inspection, write the mesh-current equations for the circuit
*Refer to in-class illustration, textbook
Circuit Analysis I 20
3.7 Nodal versus Mesh Analysis (1)
To select the method that results in the smaller number of equations. For example:
1. Choose nodal analysis for circuit with fewer nodes than meshes.
*Choose mesh analysis for circuit with fewer meshes than nodes.
*Networks that contain many series connected elements, voltage sources, or supermeshes are more suitable for mesh analysis.
*Networks with parallel-connected elements, current sources, or supernodes are more suitable for nodal analysis.
2. If node voltages are required, it may be expedient to apply nodal analysis. If branch or mesh currents are required, it may be better to use mesh analysis.