ENSC2003 - Lecture 5

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ENSC2003 - Lecture 4
Systematic Approaches - Slides cont.

Node-To-Datum: Supernodes

• You cannot use NTD to solve circuits where a voltage source is connected between two non-reference nodes

  

• The two non-reference nodes form a signal supernode

  • Within a supernode, voltage difference between two nodes inside are equal to voltage supplied by the voltage source

In the example above: $V_C-V_B=5V$, this can be subbed back into our KCL equations to solve them

Mesh Analysis

• A mesh is a closed loop that cannot contain any smaller closed loops inside of it -> the smallest closed loops possible
  • The circuit above has four meshes, one in each square
• We use a theoretical mesh current to represent a current circulating (clockwise) around the mesh
  • Current does not exist in reality and is only used in analysis

The total current through a component at the intersection of two mesh elements is the sum of both mesh currents

• Mesh current -> ($+$) if current through element also flows in the same direction, otherwise mesh current -> ($-$)

Steps for Mesh Analysis:

1. Choose a set of mesh currents
2. Write KVL equations around each mesh to obtain set of equations in terms of the mesh currents
3. Solve equations to obtain mesh currents
4. Determine individual element currents and voltages from this

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ENSC2003 - Lecture 6