Basic Pspice Instructions Stuart Tewksbury

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Basic Pspice InstructionsStuart Tewksbury

• These notes provide a quick tour through the
  drawing of a schematic using Orcads Pspice
  version 9. They are intended to assist the
  student in learning to use Pspice for E245 and
  E246. After completing this simple tutorial, the
  student is encouraged to draw upon Pspice in the
  verification that solutions to homework (analytic
  problems) are correct. Pspice verifications can
  be included along with the homework problems in
  E245 if the student so desires.
• NOTE Students have had difficulties replicating
  the following tutorial due to incorrect setting
  the initial mode. When you enter the Orcad
  directory, you will find a number of files.
  Start as follows.
• Rather than opening the PSpice Demo executable,
  open Capture CIS Demo.
• When starting a new project, make sure the
  Analog or Mixed-Signal Circuit Wizard mode is
  selected.

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Click in schematic capture window and selected
component appears on screen below. Click again
and another of the same component appears.
The next page shows addition of resistors
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Rotate by right-clicking while adding components
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Next, add wires to connect elements
To make wires, first click on one side of an
element, move mouse to side of other element you
want to connect to and click again.
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Wire now connects VDC to R1. Repeat process to
connect other elements.
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Circuit is now wired. Next MUST add ground
connection.
Click here to select ground
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Next, we add a ground (REQUIRED)
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Here, ground has been added and wired to circuit.
Circuit is now complete. Save it. There are
errors in the circuit which will interfere with
simulation. (a) voltage source is set to 0V and
will need to be changed. (b) wire connection to
ground not complete
Next under Pspice menu, you will set up the
simulation
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These are the default settings. You will adjust
them, depending on the time constants of your
circuit. Here, we are simulating a DC circuit so
the time definition is not important. But, well
change it anyways.
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Here, we have changed the time parameter, which
will determine the default times for the
transient plots.
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The error here is because our ground was not
properly connected.
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Here, we have corrected the faulty connection to
the ground. Ignore the extra ground symbol. My
error but it doesnt matter. Next, rerun the
simulation (run under the Pspice pull-down
menu).
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The simulation ran successfully (see bottom
left). However, nothing appears. Thats because
we must add traces. You select traces by
clicking on the Trace pull-down menu and the
add new trace item.
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This menu appears when you add a trace, allowing
you to select what you want to see. Well select
the voltage across the resstor labeled R2 in the
circuit diagram.
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Whoops! The voltage shown is zero. Simulation
ran correctly but whats wrong. Checking back on
the circuit, we would see that the voltage source
had not been set to a voltage yet. So, well go
back and set the voltage of the voltage source,
by double clicking on the voltage value displayed.
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Double clicking on the value given for the
voltage source brings up this menu. Here, you
can set the value. If you enter a value and also
check Name Only, that value is not used. So,
you must also check either Value only or Name
and value. When done, click OK.
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Here, we have changed the voltage from 0V to 5V.
Generally, you will need to specify the units.
You can also use abbreviations for powers of
10.Mega millionskilo k thousandsm
,milliu micron nanop picoetc
After correcting voltage, run simulation again.
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And, finally, heres the correct result. You
could also have clicked on DC analysis and
obtained simply a text value of the voltage. You
should play around with the other setting under
the Set up Simulation window.