ECE 201 Lab 5

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DC Sweep, Transient and AC Analysis using
PSPICE EEE202 - LAB 6 2.5 of final grade
Projects and Notes prepared by Dr. Gabriele
Formicone
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OUTLINE

• Transient analysis using PSPICE
• DC sweeps in PSPICE
• 3) Plotting waveforms and sweeps in PSPICE
• 4) Project Assignment with AC analysis

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Transient analysis.
Put two resistors in series. Use the VPULSE
source in the sources library (see next slide).
Set the attributes using 1 millisecond values
for rise and fall times, 5 milliseconds for
pulse width and 10 millisecond for period. AC
and DC are set to zero. Under the Analysis pull
down menu, click on setup. Enable the transient
entry.
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The VPULSE Source
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Click on the word transient itself to get to the
transient dialogue box. In that box set the
Print step to 0.2 ms and the final time to 20
ms. Return to Analysis pull-down menu and click
on simulate. The screen should change to a
screen called probe. You can now plot various
waveforms using the add entry under the trace
pull-down menu. Add in two voltages. Are the
results what you expected?
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DC Sweep Analysis
Save the circuit, create the netlist and run
simulation.
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Examine Your Netlist
Identify where the nodes are in your circuit in
order to relate it to the Netlist. Find some
other groups in the class. Does everybody get
the same netlist?
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Now, examine the Output File
First, you should see the netlist. Then, it
tells you about some aliases. Copy them
down. Then it tells you that you didnt run any
Probe. Then it gives you the small-signal bias
solution. This includes a list of nodes and node
voltages. Is the answer correct? Then it
provides the values for the voltage source
currents and the total power dissipation. Are
these values correct?
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Doing DC Sweep Doing DC Sweep

• Enter circuit
• Click on Analysis
• Click on setup
• Click on the DC Sweep
• Click on voltage source in the sweep var type
  section
• Enter V1 as the name

• Select Linear as sweep type
• Enter 0 as start value, 10 V as end value and 1V
  as increment value.
• Click OK
• Click on Close
• Then click on simulate under analysis

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Examine Answer by running Probe
It will often show up automatically as result of
a simulation. If not, you click on run probe
under the analysis menu. Probe plots things
versus the quantity being swept. You can tell
it what you want by clicking on add trace when
probe is active. It will give you a complete menu
of everything that it can plot. You pick.
Note vertical scale is controlled by largest
trace.
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What are Aliases?
The OUTPUT file tells you that you have assigned
an alias of R1 to resistor R1, R2 to resistor
R2, etc. It also tells you for each resistor
that number 1 is one node and number 2 is the
other node. Check this out by adding in traces
for V_V1, V(R11), V(R12), V(R21) and
V(R22). Delete them by clicking on the entry
just below the plot and then hitting
delete. Verify that V(N0001) and V(N0002) are
the node voltages. The try adding the following
trace V1(R1)-V(R11)
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Now enter this circuit.
Then, sweep the current source from -5mA to 5mA
in 0.5mA steps. When done, add traces for I(I1),
I(R1) and I(R2).
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Varying a Parameter, such as a Resistance.
This is done by adding in a new Part. Get the
part PARAM out of the SPECIAL library. Also
edit the current source value attribute. When
done your screen should look like this
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Double click on the value of R2. Type R2_val in
the dialogue box as the new value and hit
OK. Double click left button on the PARAMETERS
object. Click on NAME 1 and enter R2_val (with
no curly brackets) as the value. REMEMBER TO
SAVE IT. Then, click on VALUE 1 and enter any
value you want. SAVE this value. click OK. The
new screen is
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Now, go under Analysis and choose Setup. Click on
DC sweep Pick Global Parameter as the swept
variable type. Choose linear as the Sweep
Type. Enter R2_val as the Name. Vary it from 1K
to 10K in 1K increments. Click OK and then Close
and then Simulate. Probe should come up with the
resistance value as the horizontal axis. Add
traces to show current division.
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Go back into Analysis, then Setup and then DC
sweep again. Pick Decade as the Sweep Type. A
decade is a power of 10. They might run 2 to 20
as first decade, 20 to 200 as the second, 200 to
2000 as the third, etc. Try 3 ohms as start
value, 30k as end value and use 20 points per
decade. Hit OK, Close and Simulate. Trace the
currents first. Then, try tracing the product
of I(R2) and the voltage across R2. Your plot
should peak at a R2 value of 3kW.
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More on Transient analysis.
Now, enter this circuit The source shown is
VSIN, a transient sinusoidal source. Edit its
attributes so that the amplitude is 1 volt and
the frequency is 1 kHz.
Then, under Analysis, hit setup and then click on
transient. In the resulting dialogue box, enter
10 ms for the final time and 0.05 ms for the
print step time.
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Now, lets simulate and run probe. The result
should look like this
NOTE In Probe, on the tools pull down menu, you
find an entry copy to clipboard which can be
used to copy Probe graphs into other things like
Word documents.
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Now, enter this circuit. The source shown is
VPULSE from the SOURCE.slb library. Edit the
attributes of VPULSE setting DC0, AC0, V10,
V21 TD, TR and TF all equal to 1ns PW equal to
5 ms and PER equal to 10 ms.
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Go into the transient setup dialogue box. Enter
50ns for the print time step and 50 ms for the
final. Simulate and run Probe to observe the
source and capacitor voltages. You should see
something like this
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How to simulate a switching transient problem
with PSPICE
This might depend on the specific version of
SPICE you are using.
Enter this circuit.

The switch is called Sw_tClose. It is found in
the Eval.slb library.
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Edit the attributes of the switch. Set tclose to
2 milliseconds. This means that the switch is
open initially but will suddenly close at time
t2 ms. Now, set the initial condition or
initial voltage of the capacitor. You do this by
editing the attributes of the capacitor. The
attribute IC is the initial capacitor voltage.
Try a value of 3 volts. Before you leave the
capacitor attributes, by clicking on Change
Display and then on Both name and value, you can
get SPICE to display the initial condition.
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Your schematic display should look like this.
Now, check your netlist and determine what traces
you wish to display in probe. Then, enter setup.
Under the transient dialogue box, set the print
time to 1 millisecond and the final time to 10
milliseconds. Simulate.
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Circuit 1 Lab Report
USE PSPICE to simulate the circuit above using an
AC simulation. Sweep the frequency from 1kHz to
1GHz. Plot voltages across and currents
through resistor, inductor and capacitor. Print
plots. Turn in these printed results only.
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Circuit 2 Lab Report
USE PSPICE to simulate the circuit above using an
AC simulation. Sweep the frequency from 100Hz to
200kHz. Plot voltages across and currents
through resistor, inductor and capacitor. Print
plots. Turn in these plots only. (see sample
next slide)
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Voltage
Current