Capture/PSpice Tutorial



The following is a brief introduction to PSPICE.



1.   Starting PSPICE


     To run Capture:

Select Start ® All Programs ® OrCAD 16.0 ® OrCAD Capture CIS.


     Select “Allegro PCB Design CIS L”, then click “OK”


     File ® New ® Project.


     Choose “Analog or Mixed-signal Circuit Wizard”


     Type in the name of the new project and specify the location where it will be saved.  Be sure to save it in a subdirectory (for instance, W:\ECE 443\Project 1), because PSPICE cannot re-open files that have been stored in the root directory (W:\Project 1) and your project will be lost.  The W: drive is a network drive assigned to you.


     Then you will be prompted to create a PSPICE project.  Choose “Create a Blank Project” and click ‘OK’.


     If your project did not open to the Schematic Editor then open your new folder ® open SCHEMATIC1 ® open PAGE1.



2.   Adding Libraries


     To add the parts libraries select Place® Part


     You will be prompted with a new window called “Place Part”. The parts list should be empty if the libraries have not been added. 


     Click on “Add Library” in the new window.  Select the following file



     Click cancel for now to return to the schematic screen.


     To add the ground library select Place® Ground


     You will be prompted with a new window called “Place Ground”


     Click on “Add Library” in the new window.  Select the following file




3.   Drawing the circuit in Fig. 1, Project #1


     Placing parts


      Select Place ® Part (Or just click the “Place a Part” palette)


      To retrieve r (resistor), c (capacitor), and l (inductor): select analog in the libraries and type in r, c, and l in the part name box respectively. 


      To retrieve vpulse : select source in the libraries and type in vpulse in the part name box.


      To rotate a part, select the part and type r.


      To flip a part, select the part and type h (horizontal) or v (vertical).


     Setting the part parameters


      Double click on the resistance or capacitor, and the corresponding value of  a resistance or a capacitance can be changed.


      Double click on the pulse voltage source.  Set the following parameters for the source:


                        V1 = -5 (the minimum voltage of the pulse)

                        V2 = 5   (the maximum voltage of the pulse)

                        TD = 0  (the delay from time zero of the first rising edge)

                        TR = 0  (rise time)

                        TF = 0  (fall time)

                        PW =  (pulse width) equal to or greater than 5 times of t

                        PER = (period) equal to twice the pulse width























     Wiring the components


      Use shift-w to get the wiring tool and wire the circuit. (select wire in the palette)


     Grounding the circuit


      select Place ® Ground (or just select ground in the palette).

      Select source in the libraries and select “0”



4.   Selecting the type of analysis


      After all the steps mentioned above are done, you should select PSpice ® New Simulation Profile.


Select Time Domain (Transient) in the analysis type


Set the following parameters:

                        Run to time  = twice the pulse width

      In Transient Options

                        Maximum step size = 1/1000 of Run to time



5.   Placing Markers


      From the pull down menu, select PSpice ® select Markers ® select Voltage Level.  Use this marker to calculate the voltage at the node between the two resistors Ra and Rb with respect to ground.


      From the pull-down menu, select PSpice ® select Markers ® select Voltage Differential.  Use the two markers to calculate the voltage across Ra.  Click on the upper node of Ra, then on the lower node of Ra.  You’ll see + and - signs in the markers, which indicate the reference polarity of the voltage.



6.   Simulating the circuit using PSPICE


                  Click on the pull-down menu PSpice.  Select Run.

Or, you can simply press play button in the tool box.



7.   Analyzing the results


      This series of options is performed on the OrCAD Pspice A/D output window, which should show the desired trace at this point.


     Using the cursors

Click on the pull-down menu Trace.  Select Cursor ® Display.  You will then be given access to two cursors.  One of the cursors is controlled by the left mouse button and one is controlled by the right mouse button.  A small window labeled Probe cursor gives the values at each of the cursors as well as the difference between them.


     Marking a specific voltage level

Click on the pull-down menu Plot.  Select Label ® Mark.  This will label the specific point on the graph which is pointed to by the cursor that was last moved.


     Adding a plot

Click on the pull-down menu Plot.  Select Add Plot to Window.  Another axis will be added, although at this time there will be no traces on it.  Any number of plots can be added, but using much more than two can make the printout be too crowded.


     Adding a trace

A trace can be added to the plot which is currently selected.  A specific plot is selected simply by clicking anywhere on it.  The selected plot is indicated by a SEL>> on its left side.

Click on the pull-down menu Trace.  Select Add… Then you can enter any expression containing any currents or voltages on the schematic.  This trace will then be added to the plot.


     Deleting a trace

First of all, the trace must be selected.  This is done by clicking on the name of the trace.  Then click on the pull-down menu edit.  Select Delete.



8.   Viewing the netlist


Select PSpice ® View Netlist.


The netlist gives the list of all the elements using the simple format:


      R_name node1 node2 value

      C_name node1 node2 value

      V-name node 1 node2 value


The positive current direction in an element such as a resistor is from node1 to node2.  Node1 is either the left pin for a horizontal element or the top pin for a vertical element.  By rotating the element 180 degrees one can switch the pin numbers.


The model syntax for the basic Spice simulation devices can be seen at