Mon Oct 27 11:20:20 EDT 2014
Spice DC analysis, voltages sources and Thevenin equivalent circuit
In  it is mentioned that
- Current sources and resistors mix very well as they give simple
linear systems in terms of node voltages when Kirchhoff's Current Law
(KCL) is used for every node.
- The presence of a voltage source messes up this pretty picture. See
page 10 in .
I vaguely remember running into this in class, but thinking about it,
the statement "we cannot form the matrix equations" seems a bit hard
to believe. What exactly is the limitation? Surely there are 3
linear equations in 3 unknowns (I1, V2, V2) in Figure 2.
I guess the point is here that when all voltage sources are replaced
with current sources, the problem is a lot easier to state since all
node voltages are variables and for each node there is a KCL equation.
No need to keep track of which voltages are variables and which are