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Circuit Analysis-II Lab Manual 2019

UNIVERSITY OF ENGINEERING & TECHNOLOGY, MARDAN

DEPARTMENT OF ELECTRICAL ENGINEERING

LAB MANUAL

EE-201L CIRCUIT ANALYSIS-II LAB

Spring 2019

Prepared By: Engr. Nayab Taj

Table of ContentsLab #01: Introduction to Simulation Software (PSPICE)...............................................................3

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Lab #02: AC/DC Resistive Network Analysis using PSPICE......................................................15

Lab #03: To Implement a Half-Wave Rectifier Circuit using PSPICE.........................................18

Lab #04: To Implement a Full-Wave Rectifier Circuit using PSPICE........................................21

Lab #05: To obtain Thevenin Equivalent circuit of a given DC circuit........................................25

Lab #06: To obtain Norton Equivalent circuit of a given DC circuit............................................30

Lab #07: To Find Unknown Voltage and Current in a Circuit Containing Dependent Voltage

Source............................................................................................................................................30

Lab #08: To Find Unknown Voltage and Current in a Circuit Containing Dependent Current

Source............................................................................................................................................36

Lab #09: To Plot Step Response of a First Order RL Series Circuit.............................................39

Lab #10: To Plot Step Response of a First Order RC Series Circuit.............................................42

Lab #11: To Plot Frequency Response of a First Order Passive Low Pass Filter.........................45

Lab #12: To Plot Frequency Response of a First Order Passive High Pass Filter........................51

Lab #13: To Plot Frequency Response of an Active Low pass/High Pass Filter..........................55

Lab #14: To Study Operational Amplifier as Integrator...............................................................64

Lab #15: Open Ended Lab (Spring 2019)......................................................................................67

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Lab #01: Introduction to Simulation Software (PSPICE)

Objectives:

To be familiar with different simulation software i.e Multisim, Proteus, OrCaD, PSPICE and MATLAB etc.

Installation, introduction and applications of PSPICE. Implementing basic electrical circuits in PSPICE using different power sources.

Theory:

PSPICE stands for “Personal Simulation program with integrated circuit emphasis”.PSPICE is a simulation software/circuit analysis tool/ testing tool which is used for analyzing different Electrical circuits. In this Lab we are using PSPICE Student Version 9.1 which is available on the internet.In the installation process remember that you must disable all your anti-virus programs.Select both the capture and schematics options during installation.

I. Opening PSpice:

After installation go to the search window and type “Schematics” and click on the icon

.

II. Drawing the circuit:

A. Getting the Parts:

The first thing that you must do is get some or all of the parts you need. This can be done by

o Clicking on the 'get new parts' button , or o Pressing "Control+G", oro Going to "Draw" and selecting "Get New Part..."

Once this box is open, select a part that you want in your circuit. This can be done by typing in the name or scrolling down the list until you find it.

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Some common parts are: o r - resistoro C - capacitor o L - inductor o d - diodeo GND_ANALOG or GND_EARTH -- this is very important, you MUST have a

ground in your circuit o VAC and VDC

Upon selecting your parts, click on the place button then click where you want it placed (somewhere on the white page with the blue dots). Don't worry about putting it in exactly the right place, it can always be moved later.

Once you have all the parts you think you need, close that box. You can always open it again later if you need more or different parts.

B. Placing the Parts: You should have most of the parts that you need at this point. Now, all you do is put them in the places that make the most sense (usually a rectangle

works well for simple circuits). Just select the part and drag it where you want it. To rotate parts so that they will fit in you circuit nicely, click on the part and press

"Ctrl+R" (or Edit "Rotate"). To flip them, press "Ctrl+F" (or Edit "Flip"). If you have any parts left over, just select them and press "Delete".

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C. Connecting the Circuit: Now that your parts are arranged well, you'll have to attach them with wires. Go up to the tool bar and

o select "Draw Wire" or o "Ctrl+W" or o go to "Draw" and select "Wire".

With the pencil looking pointer, click on one end of a part, when you move your mouse around, you should see dotted lines appear. Attach the other end of your wire to the next part in the circuit.

Repeat this until your circuit is completely wired. If you want to make a node (to make a wire go more than one place), click somewhere on

the wire and then click to the part (or the other wire). Or you can go from the part to the wire.

To get rid of the pencil, right click. If you end up with extra dots near your parts, you probably have an extra wire, select this

short wire (it will turn red), then press "Delete". If the wire doesn't go the way you want (it doesn't look the way you want), you can make

extra bends in it by clicking in different places on the way (each click will form a corner).

D. Changing the Name of the Part:

You probably don't want to keep the names C1, C2 etc., especially if you didn't put the parts in the most logical order. To change the name, double click on the present name (C1, or R1 or whatever your part is), then a box will pop up (Edit Reference Designator). In the top window, you can type in the name you want the part to have.

Please note that if you double click on the part or its value, a different box will appear.

E. Changing the Value of the Part:

If you only want to change the value of the part (if you don't want all your resistors to be 1K ohms), you can double click on the present value and a box called "Set Attribute Value" will appear. Type in the new value and press OK. Use u for micro as in uF =

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microfarad.

If you double click on the part itself, you can select VALUE and change it in this box.

F. Making Sure You Have a GND:

This is very important. You cannot do any simulation on the circuit if you don't have a ground. If you aren't sure where to put it, place it near the negative side of your voltage source.

G. Voltage and Current Bubbles: These are important if you want to measure the voltage at a point or the current going

through that point. To add voltage or current bubbles, go to the right side of the top tool bar and select

"Voltage/Level Marker" (Ctrl+M) or "Current Marker" . To get either of these, go to "Markers" and either "Voltage/Level Marker" or "Current Marker".

H. Saving:

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To save the circuit, click on the save button on the tool bar (or any other way you normally save files).

I. Printing: To print, you must first use your mouse to make a rectangle around your circuit, this is

the area of the page that will be printed. Then select print as usual. (You can select ).

III. Probe:

A. Before you do the Probe:

You have to have your circuit properly drawn and saved. There must not be any floating parts on your page (i.e. unattached devices). You should make sure that all parts have the values that you want. There are no extra wires. It is very important that you have a ground on your circuit. Make sure that you have done the Analysis Setup and that only the things you want are

enabled. B. To Start the Probe:

Click on the Simulate button on the tool bar (or Analysis, Simulate, or F11).

It will check to make sure you don't have any errors. If you do have errors, correct them. Then a new window will pop up. Here is where you can do your graphs.

C. Graphing:

If you don't have any errors, you should get a window with a black background to pop up. If you did have errors, in the bottom, left hand side, it will say what your errors were

(these may be difficult to understand, so go to "View - Output File").

D. Adding/Deleting Traces:

PSpice will automatically put some traces in. You will probably want to change them.

Go to Trace - Add Trace or on the toolbar. Then select all the traces you want. To delete traces, select them on the bottom of the graph and push Delete.

E. Doing Math: In Add Traces, there are functions that can be performed, these will add/subtract (or

whatever you chose) the lines together.

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Select the first output then either on your keyboard or on the right side, clicks the function that you wish to perform.

There are many functions here that may or may not be useful. If you want to know how to use them, you can use PSpice's Help Menu.

It is interesting to note that you can plot the phase of a value by using IP(xx), where xx is the name of the source you wish to see the phase for.

F. Labeling:

Click on Text Label on top tool bar. Type in what you want to write. Click OK You can move this around by single clicking and dragging.

G. Finding Points:

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There are Cursor buttons that allow you to find the maximum or minimum or just a point on the line. These are located on the toolbar (to the right).

Select which curve you want to look at and then select "Toggle Cursor" .

Then you can find the max, min, the slope, or the relative max or min ( is find relative max). H. Saving:

To save your probe you need to go into the tools menu and click display, this will open up a menu which will allow you to name the probe file and choose where to save it. You can also open previously saved plots from here as well.

I. Printing:

Select Print in Edit or on the toolbar . Print as usual.

IV. Analysis Menu

To open the analysis menu, click on the button.

A. AC Sweep

The AC sweep allows you to plot magnitude versus frequency for different inputs in your circuit. In the AC sweep menu, you have the choice of three types of analysis:

o Linear, o Octave and o Decade.

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These three choices describe the X-axis scaling which will be produced in probe. For example, if you choose decade then a sample of your X-axis might be 10Hz, 1kHz, 100kHz, 10MHz, etc.... Therefore, if you want to see how your circuit reacts over a very large range of frequencies choose the decade option.

You now must specify at how many points you want PSpice to calculate frequencies, and what the start and end frequency will be. That is, over what range of frequencies do you want to simulate your circuit.

B. DC Sweep

The DC sweep allows you to do various sweeps of your circuit to see how it responds to various conditions.

For all the possible sweeps, o voltage, o current,o temperature, and o parameter and global

You need to specify a start value, an end value, and the number of points you wish to calculate.

For example, you can sweep your circuit over a voltage range from 0 to 12 volts. The main two sweeps that will be most important to us at this stage are the voltage sweep and the current sweep. For these two, you need to indicate to PSpice what component you wish to sweep, for example V1 or V2.

Another excellent feature of the DC sweep in PSpice, is the ability to do a nested sweep. A nested sweep allows you to run two simultaneous sweeps to see how changes in two

different DC sources will affect your circuit. Once you've filled in the main sweep menu, click on the nested sweep button and choose

the second type of source to sweep and name it, also specifying the start and end values. (Note: In some versions of PSpice you need to click on enable nested sweep). Again, you can choose Linear, Octave or Decade, but also you can indicate your own list of values, example: 1V 10V 20V. DO NOT separate the values with commas.

C. Bias Point Detail This is a simple, but incredibly useful sweep. It will not launch Probe and so give you

nothing to plot. But by clicking on enable bias current display or enable bias voltage display, this will indicate the voltage and current at certain points within the circuit.

D. Parametric

Parametric analysis allows you to run another type of analysis (transient, sweeps) while using a range of component values using the global parameter setting. The best way to demonstrate this is with an example, we will use a resistor, but any other standard part would work just as well (capacitor, inductor).

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First, double-click the value label of the resistor that is to be varied. This will open a "Set Attribute Value" dialog box. Enter the name RVAL (including the curly braces) in place of the component value. This indicates to PSpice that the value of the resistor is a global parameter called RVAL. In order to define the RVAL parameter in is necessary to place a global parameter list somewhere on the schematic page. To do this, choose "Get New Part" from the menu and select the part named param.

Place the box anywhere on the schematic page. Now double-click on the word PARAMETERS in the box title to bring up the parameter dialog box. Set the NAME1= value to RVAL (no curly braces) and the VALUE1= value to the nominal resistance value. This nominal value is required, but it is only used if the DC bias point detail is computed. Otherwise, the value is ignored by PSpice.

Finally, go to the "Analysis Setup" menu and enable "Parametric" analysis. Open the Parametric setup dialog box and enter the sweep parameters: Name: RVAL Swept variable type: Global Parameter. Make sure the other analysis type(s) are selected in the analysis setup menu (transient, sweeps). PSpice will now automatically perform the simulation over and over, using a new value for RVAL during each run.

This isn't as important for us in the lab, but some day when you are constructing real circuits that need to function under various conditions this will be useful.

E. Temperature

The temperature option allows you to specify a temperature, or a list of temperatures (do not include commas between temperature values) for which PSpice will simulate your circuit.

For a list of temperatures that simulation is done for each specified temperature.

F. Transient

The transient analysis is probably the most important analysis you can run in PSpice, and it computes various values of your circuit over time. Two very important parameters in the transient analysis are:

o print step o final time.

The ratio of final time: print step determines how many calculations PSpice must make to plot a wave form. PSpice always defaults the start time to zero seconds and going until it reaches the user defined final time. It is incredibly important that you think about what print step you should use before running the simulation, if you make the print step too small the probe screen will be cluttered with unnecessary points making it hard to read and taking extreme amounts of time for PSpice to calculate. However, at the opposite side of that coin is the problem that if you set the print step too high you might miss important phenomenon that are occurring over very short periods of time in the circuit. Therefore, play with step time to see what works best for your circuit.

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You can set a step ceiling which will limit the size of each interval, thus increasing calculation speed. Another handy feature is the Fourier analysis, which allows you to specify your fundamental frequency and the number of harmonics you wish to see on the plot. PSpice defaults to the 9th harmonic unless you specify otherwise, but this still will allow you to decompose a square wave to see its components with sufficient detail.

V. Types of Sources

A. Voltage Sources

i. VDC

This is your basic direct current voltage source that simulates a simple battery and allows you to specify the voltage value.

ii. VAC

A few things to note about the alternating current source, first PSpice takes it to be a sine source, so if you want to simulate a cosine wave you need to add (or subtract) a 90° phase shift. There are three values which PSpice will allow you to alter, these being:

o ACMAG which is the RMS value of the voltage.o DC which is the DC offset voltageo ACPHASE which is the phase angle of the voltage

Note that the phase angle if left unspecified will be set by default to 0°

iii. VSIN

The SIN type of source is a damped sine with time delay, phase shift and a DC offset. If you want to run a transient analysis you need to use the VSIN see how AC will affect your circuit over time. Do not use this type of source for a phasor or frequency sweep analysis, VAC would be appropriate for that.

o DC the DC component of the sine wave12


o AC the AC value of the sine waveo Voff is the DC offset value. It should be set to zero if you need a pure

sinusoid.o Vamplitude is the undamped amplitude of the sinusoid; i.e., the peak

value measured from zero if there were no DC offset value. o FREQ is the frequency in Hz of the sinusoid. o TD is the time delay in seconds. Set this to zero for the normal sinusoid.o DF is the damping factor. Also set this to zero for the normal sinusoid.o PHASE is the phase advance in degrees. Set this to 90 if you need a

cosine wave form. Note that the normal usage of this source type is to set Voff, TD and DF to zero

as this will give you a 'nice' sine wave.

iv. VPULSE

The VPULSE is often used for a transient simulation of a circuit where we want to make it act like a square wave source. It should never be used in a frequency response study because PSpice assumes it is in the time domain, and therefore your probe plot will give you inaccurate results.

o DC the DC component of the wave.o AC the AC component of the wave.o V1 is the value when the pulse is not "on." So, for a square wave, the

value when the wave is 'low'. This can be zero or negative as required. For a pulsed current source, the units would be "amps" instead of "volts."

o V2 is the value when the pulse is fully turned 'on'. This can also be zero or negative. (Obviously, V1 and V2 should not be equal.) Again, the units would be "amps" if this were a current pulse.

o TD is the time delay. The default units are seconds. The time delay may be zero, but not negative.

o TR is the rise time of the pulse. PSpice allows this value to be zero, but zero rise time may cause convergence problems in some transient analysis simulations. The default units are seconds.

o TF is the fall time in seconds of the pulse.o TW is the pulse width. This is the time in seconds that the pulse is fully

on.o PER is the period and is the total time in seconds of the pulse.

This is a very important source for us because we do a lot of work with the square wave on the wave generator to see how various components and circuits respond to it.

B. Current Sources

For any of the previous discussed voltage sources, there exist the exact source except that they produce current. There is one thing that should be mentioned; current sources in

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PSpice get a little confusing. For those current sources whose circuit symbol has an arrow, you must point the arrow in the direction of conventionally flowing current. This applies to all current sources, including AC and DC. Therefore, placing the current source in the circuit backwards with seemingly incorrect polarities will give the correct results.

An interesting little feature under the marker’s menu is the ability to add markers to your circuit so you can see where the current and voltage have imaginary values in the circuit, and the phase of your source at any point in the circuit.

Task: Verify Ohm’s law using Bias point detail analysis type.

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Lab #02: AC/DC Resistive Network Analysis using PSPICE

Objectives:To be familiar with the usage of VDC, VSIN and VAC for Resistive circuits and analyzing the output graphs.

1. AC Resistive Network Analysis

Circuit Diagram:

Output Graph:

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Required Steps:

1) Design the Circuit Shown in Figure.2) Click on Setup Analysis and select Transient.3) Enter Print step 0s and Final time 100ms and turn on skip initial condition.4) Click on Simulate.5) Go to Trace and select Add Trace.6) Now click on Vin and Vout.7) Graph will be displayed.8) Find theoretical values of current, output voltage and power.9) Go to view and then to output file and match the readings to theoretical values.

2. DC Resistive Circuit Analysis

Required Steps:

1) Design the Circuit Shown in Figure.2) Click on Setup Analysis and select Transient.3) Enter Print step 0s and Final time 100ms and turn on skip initial condition.4) Click on Simulate.5) Go to Trace and select Add Trace.6) Now click on Vin and Vout.7) Graph will be displayed.

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Output Graph:

Task: Implement above circuits on hardware available in Laboratory.

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Lab #03: To Implement a Half-Wave Rectifier Circuit using PSPICE

Objectives:To be familiar with the construction and working of Half-wave Rectifier circuit using PSPICE software as well as available hardware.

Theory:Rectification: The process of conversion of alternating current to pulsating direct current is called rectification.

A diode is connected to an AC source and to a load resistor, forming a half-wave rectifier. Half-wave rectifier allows current through the load only during one-half cycle.

The average value of the half-wave rectifier output voltage can be measure on DC voltmeter.Mathematically, average value of the half-wave rectifier can be calculated by finding area under the curve over a full cycle. (full cycle= 2π).Then the average value of voltage is given by:

Vavg= 12 π∫0

π

(Vpeck sinx+0 ) dx

=1

2 π (Vp)∫0

π

sinxdx

=1

2 π (Vp)[ – ( cosπ – cos 0)]

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=1

2 π (Vp)[2]¿Vpπ .

Apparatus Required for Practical Work: AC source (from functional generator). One Resistor (i.e. 1kΩ). One diode. Digital multi-meter (DMM). Oscilloscope. Jumpers.

Circuit Diagram:

Output Graph :

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Required Steps:

1) Design Circuit as shown in Diagram.2) Go to Setup Analysis and select Transient.

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3) Enter Print Step 0ms and Final time 20ms.4) Click on Simulate and then Add trace.5) Select Vin and Vout.6) Result will be displayed.

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Lab #04: To Implement a Full-Wave Rectifier Circuit using PSPICE

Objectives:

To be familiar with working and application of Full wave Rectifier circuit.

Theory:

A full-wave rectifier allows unidirectional (one-way) current through the load during the entire 360 degree of the input cycle. The result of full-wave rectification is an input voltage with a frequency twice the input frequency that pulsates every half-cycle of the input.

Average voltage value of a full-wave rectifier circuit is equal to twice of the average value of a half-wave rectifier circuit output. Can be measure on DC voltmeter. Mathematically,

Vavg=2Vpπ .

During the first half cycle.

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r

e

Full-wave Rectifier Circuit V0 inV 0 VoutV

I

0–

+

outVLR2D

1D

4D

3D

inV

–

+

–

+


During the second half-cycle.

Apparatus Required for Practical Work :

AC source (from functional generator). One resistor (i.e. 1kΩ). Four diodes. Digital multi-meter (DMM). Oscilloscope. Jumpers.

Required Steps in PSPICE:1) Design Circuit as shown in Diagram.

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I

0–

+

outVLR2D

1D

4D

3D

inV

F

+

–

+

–


2) Go to Setup Analysis and Select Transient.3) Enter Print Step 0ms and Final time 20ms.4) Click on Simulate and select Add Trace.

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5) Select Vout and result will be displayed.

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Lab #05: To obtain Thevenin Equivalent circuit of a given DC circuit

Objectives: 1. To be familiar with D.C Sweep in PSPICE.2. To understand how a complex circuit can be simplified using Thevenin’s theorem.

Theory:

Thevenin's Theorem:

Thevenin’s theorem can be used as a type of circuit analysis method and is particularly useful in the analysis of complicated circuits consisting of one or more voltage or current source and resistors that are arranged in the usual parallel and series connections.

“Any linear combination of voltage and/or current source and resistances can be replaced by a single voltage source called Thevenin’s voltage (Vth) in series with single resistor called Thevenin’s resistance (Rth)”.

Circuit Diagram:

Method 1: Using Theoretical calculations

1. Remove the load resistor RL 2. Find the total resistance Rth of the remaining circuit by shorting all voltage sources and by open circuiting all the current sources.

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3. Find voltage Vth by the usual circuit analysis methods.

4. Connect the Thevenin’s Voltage (Vth) And Thevenin’s Resistance (Rth) in series with load as shown. 5. Find the current flowing through the load resistor RL.

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Method 2: Using PSPICE

In this method Thevenin resistance Rth is determined from voltage vs current graph and is equal to the negative of the slope. (Negative because of decreasing slope)

Rth= -Slope = -(Y2-Y1) / (X2-X1)

Rth= - Slope = - Y 2−Y 1X 2−X 1 = -

Change∈Voltage (ΔV )Change∈Current (ΔI )

Design the given Circuit.

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Replace RL by IDC having value of 0A.

Go to Setup Analysis and Select DC Sweep. Select current source and enter Name ‘I1’, start value ‘0’, End Value ‘1’ and Increment ‘1m’

Now click on Simulate and select Add Trace. Select Vout and find Values from the Slope.

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Rth= - Slope = - (Y2-Y1) / (X2-X1)

Rth= - Slope = - Y 2−Y 1X 2−X 1 = -

Change∈Voltage (ΔV )Change∈Current (ΔI ) = - 5−(−495)

1−0 = 500 Ω

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Lab #06: To obtain Norton Equivalent circuit of a given DC circuit

Objectives: 1. To be familiar with D.C Sweep in PSPICE.2. To understand how a complex circuit can be simplified using Norton’s theorem.

Theory:

Norton’s Theorem

Norton’s theorem is an analytical method used to change a complex circuit into a simple equivalent circuit consisting of a single resistance in parallel with a current source.

Any two terminal linear network that constitute independent sources and linear resistances can be replaced with an equivalent circuit, consisting of a current source with a parallel resistor. Magnitude of this equivalent current source is equal to the short circuit current flowing through the load terminals and the equivalent resistance is the resistance at the load terminals, when all the sources in a given circuit are replaced by their internal resistances.

Method1: Using Theoretical calculations

1. Remove the load resistor RL or component concerned.2. Find equivalent resistance / Norton Resistance (Rn) by shorting all voltage sources or by open circuiting all the current sources.3. Find the short current called Norton’s equivalent current (In) by placing a shorting link on the output terminals A and B as shown.4. Find the current flowing through the load resistor RL.

Method 2: Using PSPICE

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Find the Norton current (In) by the basic procedure of Norton’s theorem.

For Norton resistance (Rn) find the slope of the current Vs voltage plot or I-V plot.

Slope = Y 2−Y 1X 2−X 1

Slope = Change∈Current (ΔI )Change∈Voltage (ΔV )

Norton’s Resistance = RN = 1

Slope

Steps: Design Circuit as shown in Diagram. Replace RL by VDC having value of 0v. Connect Current marker at negative terminal of V2.

Go to Setup Analysis and select DC Sweep. Select Voltage source and enter Name ‘V2’, Start value ‘0’ , End value ‘1’ and Increment ‘1m’ (1milli volt).

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Click on simulate.

Isc = -6.45 mA (current at voltage=0v)Y1= -6.45 mA, X1=0V, Y2= -4.5mA, X2=1VSlope = (Y2-Y1)/(X2-X1) Slope = 0.00195, RN = 1/Slope = 513

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Lab #07: To Find Unknown Voltage and Current in a Circuit Containing

Dependent Voltage Source

Objectives: To be able to analyze circuits containing voltage-controlled voltage source (VCVS) and current-controlled voltage source (CCVS).

Theory:

A dependent source is a voltage source or a current source whose value depends on a voltage or current elsewhere in the network.

Voltage Dependent Sources: Dependent Voltage Source or controlled voltage source, provides a voltage supply whose magnitude depends on either the voltage across or current flowing through some other circuit element. A dependent voltage source is indicated with a diamond shape and are used as equivalent electrical sources for many electronic devices, such as transistors and operational amplifiers.

There are four types of dependent sources which are given with PSPICE name (This name will be specific for a specific type of voltage dependent source in PSPICE) and shape in the following.

S # Description PSPICE Name PSPICE Symbol

1 Voltage Controlled Voltage Source (VCVS).

E

2 Current Controlled Current Source (CCCS).

F

3 Current Controlled Voltage Source (CCVS).

G

4 Current Controlled Voltage Source (CCVS).

H

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Task 1: Circuit containing Voltage Controlled Voltage Source

Design Circuit as shown in Diagram. For VcVs search ‘E’.

Click on ‘Enable Bias Voltage Display’ & ‘Enable Bias Current Display’.

Results will be displayed.

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Task 2: Circuit containing Voltage Controlled Voltage source & Current controlled voltage

source

Design Circuit as shown in Diagram. For VcVs search ‘E’ and for CcVs search ‘H’. Click on ‘Enable Bias Voltage Display’ & ‘Enable Bias Current Display’. Results will be displayed.

36


Lab #08: To Find Unknown Voltage and Current in a Circuit Containing

Dependent Current Source

Objectives: To be able to analyze circuits containing voltage-controlled current source (VCCS) and current-controlled Current source (CCCS).

Theory:

Current Dependent Sources: Dependent Current Source or controlled Current source, provides a

current supply whose magnitude depends on either the voltage across or current flowing through

some other circuit element. A dependent current source is indicated with a diamond shape and

are used as equivalent electrical sources for many electronic devices, such as transistors and

operational amplifiers.

In PSPICE there are two types of current dependent sourcesCurrent Controlled Current Source (CCCS). Represented by “H” in PSPICE.Voltage Controlled Current Source (VCCS). Represented by “G” in PSPICE.

Steps for designing and simulation of given circuit in PSPICE:

Design Circuit as shown in Diagram. For VcCs search ‘G’ and for CcCs search ‘H’. Set gain for CcCs “H” = 3. Set gain for VcCs “G” = 2. Assign the currents for applying KCL to the node as shown.

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Analyzing the above Circuit in PSPICE: According to KCL. Sum of currents entering the node is equal to sum of the current leaving the node. I1+I2 = I3+I4 Click on ‘Enable Bias Voltage Display’ & ‘Enable Bias Current Display’. Results will be displayed.

Hence,

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I1= 3.6A I2= 7.2A I3= 2.7A I4= 8.1A.Putting values in KCL Equation.3.6+7.2 = 2.7+8.1

Hence proved.

Also, for the above circuit voltage across each of the resistor is 3.6V.

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Lab# 09: To Plot Step Response of a First Order RL Series Circuit

Objectives:

To be familiar with the behavior of inductor that how it acts across DC. To be familiar with Transient analysis of a circuit in PSPICE.

Theory:

There are three types of responses of an electrical circuit. Step Response:

This is when we consider the currents and voltages that arise when energy is being acquired by an inductor or capacitor due to the sudden application of a DC voltage.

Natural Response:This is when we consider the currents and voltages that arise when stored energy in an inductor or capacitor is suddenly released to a resistive network.

Forced sinusoidal response:This is when we consider the currents and voltages that arise when an inductor is being driven by a sinusoidal voltage source.

However, in this lab we will study only the step response of RL circuit.

Consider figure 9.1 having inductor (L), resistor (R) and a time switch.After we close the switch of the given circuit Kirchhoff’s' voltage law can be applied which gives:

Then rearranging the above equation:

We now integrate each side and using x and y as variables for the integration we get:

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where I0 is the current at time t=0 and i(t) is the current at any time after 0. Taking inverse logs and rearranging gives us the following equation:

When the initial energy in the inductor is 0, I0 is zero hence the above becomes:

Steps in PSPICE:

a. Design Circuit as shown in diagram.

Figure 9.1

b. Go to step Analysis and select transient.

c. Enter print step ‘0’, Final time ‘1000ms’, No print delay ‘0’ and check ‘Skip initial

transient solution’.

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d. Now add trace I(L1) and V1(L1).e. Results will be displayed.

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Lab# 10: To Plot Step Response of a First Order RC Series Circuit

Objectives:

To be familiar with the behavior of Capacitor that how it acts across DC. To be familiar with Transient analysis of RC circuit in PSPICE.

Theory:

If we consider the following circuit:

we can use a method like that in lab number 9 to arrive at the expression for the voltage, which is:

Steps to plot Step Response in PSPICE:

a. Design Circuit as shown in diagram.

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b. Go to step Analysis and select transient.c. Enter print step ‘0ns’, Final time ‘3ms’, No print delay ‘0’ and check ‘Skip initial

transient solution’.

d. Now add trace I(C1) and V1(C1) one by one.e. Results will be displayed.

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Lab# 11: To Plot Frequency Response of a First Order Passive Low

Pass Filter

Objectives:To understand working and designing of Passive RC, RL and RLC Low pass filter with PSPICE software.

Theory:A filter is a frequency selective network capable of passing certain frequencies while attenuating other frequencies. Thus, a filter can extract important frequencies from signals that also contain undesirable or irrelevant frequencies.

A general overview of filters is given in the following figure.

Passive filters are most responsive to a frequency range from roughly 100Hz to 300MHz. The limitation on the lower end is a result of the fact that at low frequencies the inductance or capacitance would have to be quite large. The upper-frequency limit is due to the effect of parasitic capacitances and inductances. Careful design practices can extend the use of passive circuits well into the gigahertz range.

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Low Pass Filters:

Low pass filters are used to remove or attenuate the higher frequencies in circuits such as audio

amplifiers; they give the required

frequency response to the amplifier circuit.

The frequency at which the low pass filter

starts to reduce the amplitude of a signal

can be made adjustable. This technique

can be used in an audio amplifier as a "TONE" or "TREBLE CUT" control. RL low pass filters

and RC high pass filters are also used in speaker systems to route appropriate bands of

frequencies to different designs of speakers (i.e. ´ Woofers´ for low frequency, and ´Tweeters´

for high frequency reproduction). In this application the combination of high and low pass filters

is called a "crossover filter".

Both RC and RL Low pass filters that remove practically ALL frequencies above just a few Hz are used in power supply circuits, where only DC (zero Hz) is required at the output.

Steps for designing passive low pass filters in PSPICE:

Task 1: Plot frequency response of a passive low pass RC Circuit

Draw the circuit as shown in diagram.

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Go to setup Analysis and select AC Sweep.

Select AC sweep type ‘decade’ and Sweep parameters i.e start frequency ‘100’ & End

frequency ‘100k’.

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Now add trace ‘Vout’ and find values from Toggle cursor (Cursor point).

Task 2: Plot frequency response of a passive low pass LR Circuit.

Design circuits as shown in diagram.


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Select AC sweep type ‘decade’ and Sweep parameters i.e start frequency ‘100’ & End frequency ‘100k’.

Now add trace ‘Vout’ and find values from Toggle cursor (Cursor point).

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Lab# 12: To Plot Frequency Response of a First Order Passive High

Pass Filter

Objectives:To understand working and designing of Passive RC, RL and RLC High pass filter with PSPICE software.

Theory:

High Pass Filters:

High pass filters are used to remove or attenuate the lower frequencies in amplifiers, especially audio amplifiers where it may be called a "BASS CUT" circuit.

Steps in PSPICE:

Task 1: Plot frequency response of a first order passive RC high pass filter:

Draw the circuit as shown in figure.




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Now add trace ‘Vout’ and find values using Toggle cursor (Cursor point).

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Task 2: Plot frequency response of a first order passive RL high pass filter: Design circuits as shown in diagrams.


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Now add trace ‘Vout’ and find values from Toggle cursor(Cursor point).

2.1.1.

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Lab# 13: To Plot Frequency Response of an Active Low pass/High

Pass Filter

Objectives:

To learn designing and advantages of Active filters over passive filters. To analyze the frequency response of Low and High pass active filter using PSPICE

software.

Theory:

Active filters can deal with very low frequencies (approaching 0 Hz), and they can provide voltage gain (passive filters cannot). Active filters can be used to design high-order filters without the use of inductors; this is important because inductors are problematic in the context of integrated-circuit manufacturing techniques. However, active filters are less suitable for very-high-frequency applications because of amplifier bandwidth limitations. Radio-frequency circuits must often utilize passive filters.

Active Low Pass Filters:

By combining a basic RC/RL Low Pass Filter circuit with an Operational Amplifier, we can create an Active Low Pass Filter circuit complete with amplification.

I. First Order Low Pass Filter with unity Feedback:

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Where:

AF = the pass band gain of the filter, (1 + R2/R1)

ƒ = the frequency of the input signal in Hertz, (Hz)

ƒc = the cut-off frequency in Hertz, (Hz)

II. Active Low Pass Filter with Amplification

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III. Frequency Response Curve

Active High Pass Filters:

An Active High Pass Filter can be created by combining a passive RC filter network with an

operational amplifier to produce a high pass filter with amplification.

I. First Order High Pass Filter

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II. Active High Pass Filter with Amplification

Where:

AF = the Pass band Gain of the filter, ( 1 + R2/R1 )

ƒ = the Frequency of the Input Signal in Hertz, (Hz)

ƒc = the Cut-off Frequency in Hertz, (Hz)

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III. Frequency Response Curve

Steps in PSPICE:

Task 1: Active Low Pass filter

Design circuits as shown in diagrams.


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Now add trace ‘Vout & Vin’.

Result will be displayed.

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Task 2: Low pass filter with Unity Feedback

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Task 3: Active High Pass Filter

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Lab# 14: To Study Operational Amplifier as Integrator

Objectives:

To study different characteristics of Operational Amplifier circuit. To be familiar that how Op-Amp integrator circuit performs calculus operations in analogue

computers and its usage in analogue-to-digital converters, ramp generators and in wave shaping applications.

Theory:

Operational amplifiers can be used as part of a positive or negative feedback amplifier or as an adder or subtractor type circuit using just pure resistances in both the input and the feedback loop.

But what if we change the purely resistive (Rƒ) feedback element of an inverting amplifier to that of a frequency dependent reactance, (X) type complex element, such as a Capacitor, C. What would be the effect on the op-amps output voltage over its frequency range.

By replacing this feedback resistance with a capacitor, we now have an RC Network connected across the operational amplifiers feedback path producing another type of operational amplifier circuit commonly called an Op-amp Integrator circuit as shown in the figure.

Op-amp Integrator is an operational amplifier circuit that performs the mathematical operation of Integration, that is we can cause the output to respond to changes in the input voltage over time as the op-amp integrator produces an output voltage which is proportional to the integral of the input voltage.

Output Voltage:

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Where If is the current flowing through capacitor, Q is the charge stored by capacitor.

According to the capacitor equation Q=CV.

If the input impedance of the op-amp is infinite (ideal op-amp), no current flows into the op-amp terminal. Therefore, the nodal equation at the inverting input terminal is given as:

Where Iin is the input current flowing through the resistor.

From which we derive an ideal voltage output for the Op-amp Integrator as:

For simplicity we can write it as:

Where: ω = 2πƒ and the output voltage Vout is a constant 1/RC times the integral of the input voltage Vin with respect to time. The minus sign (–) indicates a 180o phase shift because the input signal is connected directly to the inverting input terminal of the op-amp.

Steps for Making Circuit in PSPICE:

Design circuits as shown in diagrams.


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Now add trace ‘Vout & Vin’.

Result will be displayed.

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Lab# 15: Open Ended Lab (Spring 2019)

Open Ended Lab

Circuit Analysis-II Lab (EE-201L)

Task No. 01:

Design a Third order Low pass Active filter using PSPICE such that overall voltage gain of the system is 2.

Calculate the high cut-off frequency assuming the frequency determining capacitors and resistors are equal.

Explain the Roll off factor and voltage gain of each stage by plotting a computer curve. Explain the tradeoffs between designing high order and low order filters in terms of accuracy and

complexity.At the end of lab, you are required to submit your report explaining the above tasks.

1. Viva (Marks = 3)

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Student Name

Registration No.

Class

Total Marks 17 Marks Obtained

Unsatisfactory (1) Very Good (2) Excellent (3) MarksThe student shows an undeveloped knowledge and application of objectives. Shows little or no creativity in open ended task.

The student demonstrates knowledge and application of radial balance and shows creativity in open ended task.

The student shows an advanced knowledge and application of the objectives and shows excellent creativity in open ended task.


2. Simulation (Marks = 4)Unsatisfactory (1) Good (2) Very Good (3) Excellent (4) Marks

The open-ended task was complete but did not work as required; needed several major modifications.

The open-ended task was complete but did not work as required; needed some minor modifications.

The open-ended task was complete and worked but needed few minor modifications.

The open-ended task was 100% complete and worked according to the task description.

3. Time Management (Marks = 4)Unsatisfactory (1) Good (2) Very Good (3) Excellent (4) Marks

Original Timeline is not followed; Project lagging.

Original timeline is not followed exactly; exceptions were not properly handled.

Original timeline is not followed exactly due to unforeseen circumstances.

Original timeline is followed and met.

Range of resources

EA1: Involve the use of diverse resources (and for this purposeresources include people, money, equipment, materials,information and technologies).

Level of interactions

X EA2: Require resolution of significant problems arising frominteractions between wide-ranging or conflicting technical,engineering or other issues.

Innovation EA3: Involve creative use of engineering principlesand research-based knowledge in novel ways.

Consequences to societyand the environment

EA4: Have significant consequences in a range of contexts,characterized by difficulty of prediction and mitigation.

Familiarity EA5: Can extend beyond previous knowledge

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4. Report (Marks = 6)

3 2 1 0

Report

Format

Format followed are as per standard; Allsections of the report follow given sequence

Format followed are as per standard; Allsections of the report follow given sequence

Format of sections is as per standard; Not allsections of the report follow given sequence

Standard format is not followed at all with no references

Technical Contents

In-depth Knowledge of the theory related to the task is presented with clarity.

Execution of assigned task is presented with thorough details

Knowledge of the theory related to the task is presented with clarity.

Execution of assigned task is presented with thorough details

Knowledge of the theory related to the task is presented with clarity.

Execution of assigned task is presented with sufficient details

Knowledge of the theory related to the task is clearly missing.

Execution of assigned task lacks details

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