PHYS345 Class 5

Quote of the Day -- Question of the Day

Source Substitution

Review of Mesh and Nodal Analysis
      Mixed Source Example solved by Mesh Analysis and by Nodal Analysis

Thévenin's Theorem

Any two-terminal linear circuit can be replaced with a voltage source in series with a resistance which will produce the same effects at the terminals. VTh is the open-circuit voltage Voc between the two terminals of the circuit that the Thevenin generator is replacing. RTh is the ratio of Voc to the short-circuit current Isc. In linear circuits, this is equivalent to "killing" the sources and evaluating the resistance between the terminals. Voltage sources are killed by shorting them; current sources are killed by opening them.

Detailed Example of Thévenin Approach

      Concept Check: Thévenin's Theorem

Norton's Theorem

Any two-terminal linear circuit can be replaced with a current source in parallel with a resistance which will produce the same effects at the terminals. IN is the short-circuit current Isc of the circuit that the Norton generator is replacing. Again, RN is the ratio of Voc to the short-circuit current Isc. Note that for a given circuit, RN = RTh.

Detailed Example of Norton Approach

      Concept Check: Norton's Theorem

"http://www.physics.udel.edu/~watson/phys345/class/05.html"
Last updated Sept. 13, 1999.
Copyright George Watson, Univ. of Delaware, 1999.