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364 ⏐⏐⏐ NETWORK THEOREMS
FIG. 9.120
Using PSpice to plot the power to R L for a range of values for R L.
screen. Select a spot near Rval, and deposit the rectangle. The result
is PARAMETERS: as shown in Fig. 9.120.
Next double-click on PARAMETERS: to obtain a Property Editor
dialog box which should have SCHEMATIC1:PAGE1 in the second
column from the left. Now select the New Column option from
the top list of choices to obtain the Add New Column dialog box.
Enter the Name:Rval and Value:1 followed by an OK to leave the
dialog box. The result is a return to the Property Editor dialog box
but with Rval and its value (below Rval) added to the horizontal list.
Now select Rval/1 by clicking on Rval to surround Rval by a dashed
line and add a black background around the 1. Choose Display to
produce the Display Properties dialog box, and select Name and
Value followed by OK. Then exit the Property Editor dialog box (X)
to obtain the screen of Fig. 9.120. Note that now the first value (1 �)
of Rval is displayed.
We are now ready to set up the simulation process. Select the New
Simulation Profile key to obtain the New Simulation dialog box.
Enter DC Sweep under Name followed by Create. The Simulation
Settings-DC Sweep dialog box will appear. After selecting Analysis,
select DC Sweep under the Analysis type heading. Then leave the Primary
Sweep under the Options heading, and select Global parameter
under the Sweep variable. The Parameter name should then be
entered as Rval. For the Sweep type, the Start value should be 1 �;
but if we use 1 �, the curve to be generated will start at 1 �, leaving a
blank from 0 to 1 �. The curve will look incomplete. To solve this
problem, we will select 0.001 � as the Start value (very close to 0 �)
and the End value 30.001 � with an Increment of 1 �. The values of
RL will therefore be 0.001 �, 1.001 �, 2.001 �, etc., although the plot
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