PSPICE is a circuit analysis program, developed by MicroSim Corporation, based on the well known SPICE program (Simulation Program for Integrated Circuit Evaluation) developed at the University of California-Berkeley. The PSPICE version available at The University of Mississippi can be used on a personal computer for sophisticated analysis of electric circuits of moderate size. A brief outline of SPICE commands is given below. For more details, read the SPICE or PSPICE manual which accompanies your program or other reference texts.
2. Draw a circuit in PSPICE format using elements allowed in the desired analysis
3. Create a circuit file (XXXX.CIR) using an ASCII editor,
which contains statements of 2a and 2b.
4. Execute PSPICE using the circuit file created as the input.
The .OPTIONS control statement can be used to set all options, limits, and control parameters. The flag option
can be used to suppress paging and banners for each section in the output file. It can
thus be used to minimize printer paper output in the XXX.OUT file. Please use this option
after you have learned to recognize the output file format. In addition, by using any text
editor (e.g. PED, EDIT), can be used to delete unwanted lines in the output file (XXX.OUT)
before printing the CRTL D (EOF) command. Also unwanted data can be "blocked"
using PED, or other editors, and deleted to minimize the printout requirements for
presentation of results.
Transient Circuit Analysis (.TRAN)
Transient analysis of a circuit using PSPICE is almost the same as DC analysis except a TRAN analysis statement is used. As an example, consider the circuit in Figure 2. Write a netlist describing the circuit using appropriate branch element definitions. A representative netlist follows:
Note that the "use initial condition" command is used in the TRAN statement and that the initial condition for the capacitor is specified. In this case, the applied voltage was assumed to be a step function, i.e. V1=10V t>0; thus a simple DC source was used to represent the input voltage. In other cases, a time dependent source such as a sinewave, pulse, etc., may be required. If you want output from Hewlett Packard Plotter, then PSKETCH.BAT must be executed at startup to initialize the COM port.
The PROBE statement included in the PSPICE Netlist generates a file, PROBE.DAT, for viewing the analysis on the computer monitor. If the PROBE program is executed, an output can be obtained as shown in the figure.
As in the transient example, the PROBE statement is included in the netlist so that PSPICE will generate the file PROBE.DAT for viewing the AC analysis as a function of frequency on this computer monitor. A PROBE plot output for VM(2), voltage magnitude, is shown in the figure.
F fento- 10-15
P pico- 10-12
N nano- 10-9
U micro- 10-6
M milli- 10-3
K kilo- 10+3
MEG mega- 10+6
G giga- 10+9
T tera- 10+12
MIL (0.001") 25.4×10-6
PROBE Math Capabilities
PROBE has the capability for the use of mathematical functions for data processing and
display of the data as a function of an independent variable. The following list presents
the functions available for use in generating new and different data representations in
Arithmetic expressions of output variables are allowed. The available operators are: " + ",
" - ", " * ", " / ", along with parenthesis. The
available functions are:
SGN(x) +1 (if x > 0), 0 (if x = 0), -1 (if x < 0)
LOG(x) ln(x) (log base e)
LOG10(x) log(x) (log base 10)
M(x) magnitude of x
P(x)phase of x (result of degrees)
R(x) real part of x
IMG(x) imaginary part of x
G(x) group delay of x (result in seconds)
SIN(x) sin(x) (x in radians)
COS(x) cos(x) (x in radians)
TAN(x) tan(x) (x in radians)
ATAN(x) tan-1(x) (result in radians)
ARCTAN(x) tan-1(x) (result in radians)
d(x) derivative of x with respect to the X axis variable.
s(x) integral of x over the range of the X axis variable.
AVG(x) running average of x over the range of the X axis variable.
AVGX(x,d) running average of X (from x-d to x) over the range of the X axis variable.
RMS(x) running RMS average of x over the range of the X axis variable.
DB(x) magnitude in decibels of x.
MIN(x) minimum of the real part of x.
MAX(x) maximum of the real part of x.
VM(n) - magnitude of nth node voltage
VP(n) - phase of nth node voltage in degrees
radians = degrees / 57.3