orcad pspice tutorial lab3cyphynets.lums.edu.pk/images/orcad_pspice_tutorial.pdf · o cad c t...

Lahore University of Management Sciences

School of Science & Engineering

EE 241 Introductory Electronics LabEE-241 Introductory Electronics Lab

OrCAD PSPICE TutorialOrCAD PSPICE Tutorial

O tliOutline

Introduction Introduction Circuit Drawings Circuit Simulations Simulation Results Exercises Conclusion

LUMS, EE-241 Introductory Electronics Lab, Fall 2009 2

Wh t i SPICEWhat is SPICE“Simulation Program with IC Emphasis”Simulation Program with IC Emphasis

- It is a language to represent circuit drawings in text- It is a language to represent circuit drawings in text form

- Either you can write a spice code or you can use a graphical interface circuit drawing software


Why do we need SPICE?

to provide reasonably detailed analysis of circuitscontaining the following:

– Passive components (resistors, capacitors, inductors)

Active devices (diodes transistors: BJT’s and FET’s)– Active devices (diodes, transistors: BJT s and FET s)

– Independent and dependent voltage/current sources


O CAD C t CISOrCAD Capture CIS OrCAD is the software OrCAD is the software

we will be using to simulate circuitssimulate circuits

It automatically creates a SPICE code

This tutorial is based on OrCAD 15.7 demo version


C ti j tCreating a new projectFile>>New>>ProjectFile>>New>>Project


O CADOrCAD

Schematics Window: Here you will draw your circuit schematics

Toolbar

Session Log: All the activities and errors and reported here


C ti S h tiCreating Schematics


Click: Place>>Part OR use the “Place Part” button from the toolbar

Addi Lib iAdding Libraries

If no parts are visible in the “Place Part” dialog, simply click on the “Add Library” button Default library location folder is


C:\OrCAD\OrCAD_15.7_Demo\tools\pspice\library Inside the Browse File dialog, click on any *.olb file then press Ctrl+A to select all the files

and hit the “Open File” button

COMMONLY USED SOURCESCOMMONLY USED SOURCESSource Library

VDC DC S A l i VDC DC Sweep Analysis VAC AC sweep Analysis VSIN Transient AnalysisS a s e t a ys s VPULSE Transient Analysis


Pl i P tPlacing Parts

Place your desired circuit components from their respective librariesD bl li k th t’ t t h th i l


Double-click on the component’s parameters to change their values Pay special attention to the suffixes, 1Meg, (more on this on the next slide)

SPICE S ffiSPICE SuffixesScale Suffix Meaning Scale Factor Unit Suffix Meaningg

T tera 10^ 12

G giga 10^ 9

Meg mega 10^ 6

Unit Suffix Meaning

V Volts

A Amps

Hz Hertzg g

k kilo 10^ 3

m milli 10^ -3

u micro 10^ -6

e t

Ohm Ohms

H Henry

F Farads

n nano 10^ -9

p pico 10^ -12

f femto 10^ -15

Degree degrees

-Warning: Do not confuse “Meg” & “M” SPICE will interpret “M” as “m” or “milli”

-Becareful!! writing just “1F” will mean “1 femto” and not “1 Farad”


-Unit suffixes are optional, SPICE does not need them, e.g. If you need 10 kilo Hertz frequency, for SPICE you only need to write 10k but for your own convenience you may write 10k Hz

S h tiSchematicPlace>>Wire

U i t l t l t- Use wire tool to complete your schematic

Pl G dPlace>>Ground- Remember we always

need a ground in the circuitcircuit.

- The ground we will use is the “0/SOURCE” identified by the symbol - It’s a good practice to label

d b li kiidentified by the symbol shown in the schematic your nodes by clicking

Place>>Net Alias- It helps to plot results


Ci it Si l tiCircuit SimulationsPSpice>> New Simulation ProfilePSpice>> New Simulation Profile

You can later change yoursimulation profile settings byPSpice>>Edit Simulation Profile

For this e.g. set “Run to time” for400secs considering our wave


400secs considering our waveperiod is 200secs. This will plotus two complete cycles

Si l ti R ltSimulation ResultsPSpice>>RunPSpice Run

If there aren’t any errorsin the circuit, automatically a similar window should pop-up.

Otherwise, errors would be reported in the session logreported in the session logWindow.

You can also manuallyyopen sim results by clickingPSpice>>View Simulation

Results


Plotting the ResultsPlotting the Results

– choose the variable to be plotted Y ion Y-axis

–different arithmetic operations can also be performed for e.g. V(O t)/V(I ) i i

LUMS, EE-241 Introductory Electronics Lab, Fall 2009 16Click: Trace>> Add Trace

V(Out)/V(In) i.e. gain

V lt /L l M kVoltage/Level Marker- With time you will Click to displayWith time you will

find it tedious to repeat the same steps to add traces

Click to display bias point results

steps to add traces

- You may also place a “Voltage/Level

Marker OptionsVoltage/Level Marker

a Voltage/Level Marker” where you want to observe your results and it willresults and it will automatically plot the trace for that point


point

Pl t Obt i dPlot Obtained


A i S ttiAxis Settings Axis settings can be Axis settings can be

changed by double clicking on either x or y axis

X axis variable can also be changed from “Time” to for instance “Vin”instance Vin

In your Op-Amp exercise you will be asked to plotyou will be asked to plot Vout vs. Vin, there you will use this function


C d L b lCursors and Labels- Click “Add Cursor”

- To move the cursorclick anywhere on thel t d d th

Add Cursor

plot and drag themouse pointer

S t th t th

Different Types of Cursors

Mark Label

- Set the cursor to thedesired point and click“Mark Label”

X value

Y value

- Click “Add Cursor”again to get out of the


cursor mode

So far we have learnt the basics of how to buildSo far we have learnt the basics of how to buildand simulate circuit schematics.

We also obtained simulation results for“Transient Analysis” i.e. time domain analysis.

In the following slides we will discuss the othertypes of analysis


types of analysis.

T f A l iTypes of AnalysisClick: PSpice>>Edit Simulation ProfileSelect you desired analysis type from the drop downSelect you desired analysis type from the drop down

menu

– DC Sweep: sweeps the DC source to obtain the corresponding DC outputsp g p

– AC Sweep/Noise, sweeps the frequency to obtain the frequency response

”Sweep Type” can be a linear sweep (LIN)Sweep Type can be a linear sweep (LIN), logarithmic (DEC)

– Bias Point: calculates DC node voltages and DCcurrents flowing through DC voltage sourcescurrents flowing through DC voltage sources

**SPICE has a peculiar omission… it does not giveyou every branch current, only currents throughvoltage sources, to get around this, if you need a

REMEMBER!! To run any analysis type make sure you have connected its corresponding sources, refer to slide 10


g g ybranch current, just add a dummy 0V voltage source!

AC RAC Response

LUMS, EE-241 Introductory Electronics Lab, Fall 2009 23AC response, using an AC source

Diode Exercise

1 Setup the diode circuit as1. Setup the diode circuit as shown (refer to Lab 2)

2. Run DC Sweep Analysis from 10 to +10 V andfrom -10 to +10 V and plot Vout vs. Vin

3. Build the circuit to limit lt b t 2 & 2voltage between -2 & +2

volts4. Run Transient analysis y

and plot the output5. Display Bias Points on

the schematic


the schematic

P t i SParametric SweepSweeps circuit parametersSweeps circuit parameters, for e.g. variable resistance

- Give any name to the value you want to sweep, enclosed y p,in curly brackets e.g. {R_var}, {} means it is a

l b l t d &global parameter and & R_var could be any name of your choice


your choice

P t i S C tdParametric Sweep Contd.

Place a new part on the drawing called “PARAM” (from the SPECIAL library.). Double-click its body to open its property sheet.

Within the property sheet editor, · Select the “OrCAD-PSpice” Filter to make it easier to see the

important fields.· Click the “New Column” button and add a column called R var Set· Click the New Column button and add a column called R_var. Set

its value to 1kMake sure to set R_var visible by highlighting it and clicking the

“Display” button


Under display format, select “Name and Value”· Close the property sheet.

P t i S C tdParametric Sweep Contd.

Your drawing should now look like thisYour drawing should now look like this…


P t i S Si l tiParametric Sweep SimulationClick: PSpice>>Edit Simulation p

Profile

Under Options, check Parametric Sweepp

Select Global Parameter

Enter the required fieldsEnter the required fields


Di d R tifi ti E iDiode Rectification Exercise

1 Build the diode rectification circuit from Lab 21. Build the diode rectification circuit from Lab 2

2. Use, R=1k, C=1uF and Vampl=5V

3. Simulate your circuit to obtain different ripples with different time constants.

HINT: Use parametric sweep


HINT: Use parametric sweep

O A E iOpAmp Exercise

1. Build the OpAmp circuit from Lab3. (This IC is named as uA741)2. Run transient analysis and plot Vout vs. Vin3. Use your plot to find OpAmp’s gain

LUMS, EE-241 Introductory Electronics Lab, Fall 2009 30**Note how “Net Alias” is being used to reduce wire routings

C l iConclusionBy the end of this Lab Session you shouldBy the end of this Lab Session you should know how to I Draw and Simulate SchematicsI. Draw and Simulate SchematicsII. Run Tran, AC, DC & .OP analysisIII Perform parametric sweepIII. Perform parametric sweep

And you should have obtained four plots as shownAnd you should have obtained four plots as shown on the following slides.


Di d DC SDiode DC Sweep


Li it Ci itLimiter Circuit


Diff t Ti C t tDifferent Time Constants


VTC f O AVTC of OpAmp

As you can observe there are two slopes, this phenomenon is called hysteresis. It is added to the circuit to retain the voltage level within


the designed threshold. For more details look for it online also search for “Schmitt Trigger”

orcad pspice tutorial lab3cyphynets.lums.edu.pk/images/orcad_pspice_tutorial.pdf · o cad c t...

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