down through the output file to find the currents in the voltage sources:
VOLTAGE SOURCE CURRENTS
NAME CURRENT
V_V1 - 6 .1 7 0E - 01
V_V2 3 .1 0 6E - 01
V_V3 - 3.064E - 01
V_V4 8 .1 0 6E - 01
V_V5 6 .1 0 6E - 01
TOTAL POWER DISSIPATION 1.85E + 01 WATTS
JOB CONCLUDED
PSpice uses the passive convention for the current and voltage o f all circuit elements, including voltage sources.
Noticing the small + and - signs on the voltage source symbols in Figure 4.10-3, we see that the currents
provided by PSpice are directed form left to right in sources VI and V2 and are directed from right to left in
sources V3, V4, and V5. In particular, the mesh currents are
i1 = 0.3106 A, i2 = 0.6106 A, i3 = 0.8106 A. and i4 = -0.3064 A.
4.11 HoW CAN WE CHECK . . . ?
Engineers are frequently called upon to check that a solution to a problem is indeed correct. For
example, proposed solutions to design problems must be checked to confirm that all o f the
specifications have been satisfied. In addition, computer output must be reviewed to guard against
data-entry errors, and claims made by vendors must be examined critically.
Engineering students are also asked to check the correctness of their work. For example,
occasionally just a little time remains at the end o f an exam. It is useful to be able quickly to identify
those solutions that need more work.
The following examples illustrate techniques useful for checking the solutions o f the sort of
problem discussed in this chapter.
------------------- Example 4.11 - 1 How Can We Check Node Voltages?
The circuit shown in Figure 4.11-1a was analyzed using PSpice. The PSpice output file. Figure 4.11-16, includes
the node voltages of the circuit. How can we check that these node voltages are correct?
Solution
The node equation corresponding to node 2 is
(V(2)-V(1))/100+V(2)/200+(V(2)-V(3))/100 = 0