ECE Undergraduate Laboratories
ECE 291 - Electrical Engineering Laboratory

# CIRCUIT SIMULATION

The powerful program PSPICE solves very quickly complex circuit equations for various signals and conditions and also displays results graphically.  The best way to learn it is by trying to simulate some of the circuits explored in this laboratory.  Comparison of simulations with your measurements will, hopefully, give you a better insight in the operation of these circuits.  Remember however that while simulations are very useful, they are never a substitute for real data taken from real physical systems, which are the true realm of engineering activity.

The objective of using PSPICE in this course is to give you an opportunity of comparison  the results of simulation with the real data obtained in the laboratory.  You should use PSPICE schematics with the actual values of the  components in your circuits.  For example, use the values of resistances measured by an ohmmeter rather than those given by the resistor color code. When comparing simulation curves (such as frequency responses of RC or RLC circuits) with experimental data, plot them on the same graph.  To do this, you need to export simulation curves to a graphing program, such as EXCEL or MATLAB, in which numbers from simulations and experiments can be put in different columns. Use discrete points for experimental data and continuous curves for simulations.

### Copying simulation curves from PSPICE to EXCEL

• Click on the caption label (the plotted variable) of the plot; it will become highlighted. Or, in  EDIT menu click SELECE ALL.
• From EDIT menu click COPY.
• In an open MS Excel™ worksheet click PASTE. Columns with the numbers corresponding to the axes of the  plot should appear.
• Click the graph button in the worksheet menu. Select XY (Scatter) as the chart type and a fitted line graph (without points). Finish as usual and make the plot on a separate sheet.

### Adding experimental data to the plot

• If you want to add experimental data to the plot, enter them in a new column of the worksheet
• Plot them as new data series 0n the same graph using point type plot (no line)

### Copying simulation plot (image) from PSPICE to WORD

• From FILE menu select PRINT then select option PRINT TO OFFICE DOCUMENT IMAGE WRITER
• From the Office Document Imaging window select COPY IMAGE
• Paste to MS WORD

### Copying schematics from PSPICE to WORD

• Select the area you want to copy
• From EDIT select COPY TO CLIPBOARD
• COPY to WORD