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Settings-AverageIC dialog box. Analysis is selected, and Time
Domain(Transient) is chosen under the Analysis type options. The
Run to time is set to 15 ms to encompass the period of interest, and the
Start saving data after is set at 0 s to ensure data points starting at t �
0 s. The Maximum step size is selected from 15 ms/1000 � 15 ms to
ensure 1000 data points for the plot. Click OK, and the Run PSpice
key is selected. A window will appear with a horizontal scale that
extends from 0 to 15 ms as defined above. Then the Add Trace key is
selected, and I(C) is chosen to appear in the Trace Expression below.
Click OK, and the plot of I(C) appears in the bottom of Fig. 10.80. This
time it would be nice to see the pulse waveform in the same window but
as a separate plot. Therefore, continue with Plot-Add Plot to Window-
Trace-Add Trade-V(Vpulse:�)-OK, and both plots appear as shown
in Fig. 10.80.
FIG. 10.80
The applied pulse and resulting current for the 2-mF capacitor of Fig. 10.79.
The cursors can now be used to measure the resulting average current
levels. First, select the I(C) plot to move the SEL>> notation to the
lower plot. The SEL>> defines which plot for multiplot screens is
active. Then select the Toggle cursor key, and left-click on the I(C)
plot to establish the crosshairs of the cursor. Set the value at 1 ms, and
the magnitude A1 is displayed as 4 mA. Right-click on the same plot,
and a second cursor will result that can be placed at 6 ms to get a
response of �1.33 mA (A2) as expected from Example 10.13. Both
plots were again placed in the yellow color with a wider line by rightclicking
on the curve and choosing Properties.
COMPUTER ANALYSIS ⏐⏐⏐ 425