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DEPARTMENT OF ECE ANALOG ELECTRONICS LAB

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ANURAG COLLEGE OFENGINEERING

(Approved by AICTE, New Delhi & Affiliated to JNTU-HYD)

AUSHAPUR (V), GHATKESAR (M), R.R.DIST, T.S.501301

DEPARTMENT OF ELECTRONICS AND COMMUNICATION

ENGINEERING

EC408ES: ANALOG ELECTRONICS LAB

B.Tech. II Year II Sem. L T P C

0 0 3 2

Note: Minimum 12 experiments should be conducted: Experiments are to be simulated using Multisim or P-spice or Equivalent

Simulation and then testing to be done in hardware.

LIST OF EXPERIMENTS: 1. Common Emitter Amplifier 2. Common Base Amplifier 3. Common Source amplifier 4. Two Stage RC Coupled Amplifier 5. Current Shunt Feedback Amplifier 6. Voltage Series Feedback Amplifier 7. Cascode Amplifier 8. Wien Bridge Oscillator using Transistors 9. RC Phase Shift Oscillator using Transistors 10. Class A Power Amplifier (Transformer less) 11. Class B Complementary Symmetry Amplifier 12. Hartley Oscillator 13. Colpitt’s Oscillator 14. Single Tuned Voltage Amplifier


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INDEX

S.NO. EXPERIMENT NAME PAGE

NO. 1 ELECTRONIC CIRCUIT ANALYSIS USING PSPICE 3

1.A COMMON EMITTER AMPLIFIER (SW) 22

1.B COMMON EMITTER AMPLIFIER (HW) 27

2.A COMMON BASE AMPLIFIER (SW) 29

2.B COMMON BASE AMPLIFIER (HW) 33

3.A COMMON SOURCE AMPLIFIER (SW) 35

3.B COMMON SOURCE AMPLIFIER (HW) 38

4.A TWO STAGE RC COUPLED AMPLIFIER (SW) 41

4.B TWO STAGE RC COUPLED AMPLIFIER (HW) 45

5.A CURRENT SHUNT FEEDBACK AMPLIFIER(SW) 47

5.B CURRENT SHUNT FEEDBACK AMPLIFIER(HW) 51

6.A VOLTAGE SERIES FEEDBACK AMPLIFIER(SW) 53

6.B VOLTAGE SERIES FEEDBACK AMPLIFIER 57

7.A CASCODE AMPLIFIER(SW) 59

7.B CASCODE AMPLIFIER(HW) 62

8.A RC PHASE SHIFT OSCILLATOR USING TRANSISTORS(SW) 64

8.B RC PHASE SHIFT OSCILLATOR USING TRANSISTORS(HW) 67

9.A SINGLE TUNED VOLTAGE AMPLIFIER(SW) 69

9.B SINGLE TUNED VOLTAGE AMPLIFIER(HW) 72


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TUTORIAL 1

ELECTRONIC CIRCUIT ANALYSIS USING PSPICE

1.1 AIM

1. To learn the basic features of PSpice.

2. To use PSpice for the following:

i) Analysis by using Schematic Editor.

ii) Analysis by using Circuit File Editor.

1.2 INTRODUCTION SPICE (Simulation Program with Integrated Circuit Emphasis) is a

computer simulation and modeling program used by engineers to

mathematically predict the behavior of electronic circuits. PSpice is a member of

the SPICE family of circuit simulators. In the following exercises you will use

PSpice ( OrCAD 16.0 Demo version) to solve some circuits and to determine the

quantities of interest.

SPICE can do several types of circuit analysis. They are

Non linear DC analysis: calculates DC transfer curve

Non linear transient analysis: calculates voltages and currents as a

function of time when a signal is applied

Linear AC analysis: calculates the output as afunction of frequency.

Noise analysis

Sensitivity analysis

Distortion analysis

Fourier analysis: calculates and plots the frequency spectrum.

Monte Carlo Analysis.

Pspice has analog and digital libraries of standard components. All analyses can

be done at different temperatures. The default temperature is 300K. The circuit

can contain the following components: Independent and dependent voltage and

current sources, Resistors, Capacitors, Inductors, Mutual Inductors,

Tramsmission lines, Operational amplifiers, Diodes, Bipolar transistors, MOS

transistors, JFETS, MESFETS, Digital gates.

1.2.1 File Types Used and Created by PSpice

The basic input file for PSpice is a text (ASCII) file that has the file type "CIR". The

output file always generated by PSpice is a text (ASCII) file that has the file type

"OUT. The output results in *.OUT file if you are running a DC analysis. If you are

running a transient analysis or a frequency sweep analysis, there will be too

much data for the *.OUT file. In these cases, we add a command called .PROBE to

the *.CIR file that tells PSpice to save the numerical data in a *.DAT file.

A companion file to the *.DAT file is the *.PRB file which holds initializing

information for the PROBE program. Another file called *.INC (include) files,

these enable us to store frequently used subcircuits that have not yet been added


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to a library. Then we access these *.INC files with a single command line in the

*.CIR file. Other files used with PSpice are *.LIB files where the details of complex

parts are saved

When we begin using the schematic capture program that is bundled with

PSpice, we will encounter some additional file types. These are the *.SCH (the

schematic data, itself), *.ALS (alias files) and *.NET (network connection files).

1.3 ANALYSIS BY USING CIRCUIT FILE EDITOR

1.3.3 Some Facts and Rules about PSpice

PSpice is not case sensitive.

All element names must be unique.

The first line in the data file is used as a title. It is printed at the top of

each page of output. PSpice will ignore this line as circuit data. Do not

place any actual circuit information in the first line.

There must be a node designated "0." (Zero) This is the reference node

against which all voltages are calculated.

Each node must have at least two elements attached to it.

The last line in any data file must be ".END"

All lines that are not blank (except for the title line) must have a character

in column 1, the leftmost position on the line.

o Use "*" (an asterisk) in column 1 in order to create a comment line.

o Use "+" (plus sign) in column 1 in order to continue the previous

line (for better readability of very long lines).

o Use "." (period) in column 1 followed by the rest of the "dot

command" to pass special instructions to the program.

o Use the designated letter for a part in column 1 followed by the

rest of the name for that part (no spaces in the part name).

Use "whitespace" (spaces or tabs) to separate data fields on a line.

Use ";" (semicolon) to terminate data on a line if you wish to add

commentary information on that same line.

1.3.2 How to Specify the Circuit Topology and Analysis

A PSpice input file,called source file, consists of three parts.

1. DATA STATEMENTS: description of the components and the

interconnections.

2. CONTROL STATEMENTS: tells spice what type of analysis to perform on

the circuit.

3. OUTPUT STATEMENT: specifies what outputs are to be printed or plotted.


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The order of statements:

TITLE STATEMENT

ELEMENT STATEMENTS

.

.

COMMAND (CONTROL) STATEMENT

OUTPUT STATEMENTS

.END

1.3.3 Node Designations in PSpice

In the SPICE program, users were expected to designate nodes by number or

ordinary text. E.g. "Pbus," . The only restriction is you can't embed spaces in a

node name. Use the underscore ("_") character to simulate spaces.

1.3.4 Large and Small Numbers in PSpice

PSpice is a computer program used mostly by engineers and

scientists. Accordingly, it was created with the ability to recognize the typical

metric units for numbers.

Number Prefix Common Name

1012 - "T" or "t" tera

109 - "G" or "g" giga

106 - "MEG" or "meg" mega

103 - "K" or "k" kilo

10-3 - "M" or "m" milli

10-6 - "U" or "u" micro

10-9 - "N" or "n" nano

10-12 - "P" or "p" pico

10-15 - "F" or "f" femto

An alternative to this type of notation, which is in fact, the default for PSpice

output data, is "textual scientific notation." This notation is written by typing an

"E" followed by a signed or unsigned integer indicating the power of ten. Some

examples of this notation are shown below:

656,000 = 6.56E5

-0.0000135 = -1.35E-5


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1.3.5 Data Statements to Specify the Circuit Components and

Topology

Ideal Independent DC and AC Sources

Voltage source: *name +node -node type value

Current source: *name +node –node type value

AC voltage or current source: *name +node –node type value phase(deg)

The *name of a voltage and current source must start with V and I respectively.

+node is the positive terminal node

-node is the negative terminal node

type is DC

value gives the value of the source

phase(deg) phase angle in degrees

Examples:

Va 4 2 DC 16.0V; "V" after "16.0" is optional

vs qe qc dc 24m; "QE" is +node & "qc" is -node

VWX 23 14 18k; "dc" not really needed

vwx 14 23 DC -1.8E4; same as above

Vdep 15 27 DC 0V ; V-source used as ammeter

Icap 11 0 DC 35m; 35mA flows from node 11 to 0

ix 79 24 1.7; "DC" not needed

I12 43 29 DC 1.5E-4;

I12 29 43 dc -150uA; same as above

Vac 4 1 AC 120V 30

Vba 2 5 AC 240 ; phase angle 0 degrees

Ix 3 6 AC 10.0A -45 ; phase angle -45 degrees

Isv 12 9 AC 25mA ; 25 milliamps @ 0 degrees

Vac 1 2 SIN(0 230 50);sinewave with zero dc amplitude 230V and 50Hz

frequency.

Resistors

*name +node -node value

The *name of a resistor must start with R.



Value gives the value of the source


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Examples:

Rabc 31 0 14k ; reported current from 31 to 0

Rabc 0 31 14k ; reported current changes sign

rshnt 12 15 99m ; 0.099 ohm resistor

Rbig 19 41 10MEG ; 10 meg-ohm resistor

Capacitors and Inductors

Capacitor: *name +node -node value <IC>

Inductor: *name +node -node value <IC>

The *name of a capacitor and Inductor source must start with C and L

respectively.



Value gives the value of the capacitor or inductor

<IC> (Initial Condition) initial voltage and initial current of C and L respectively.

Example:

Cfb 4 5 50u IC=20

Lag 1 2 50m IC=2.5

Semiconductor Devices

A semiconductor device is specified by two command lines: an element and

model statement. The syntax for the model statement is:

.MODEL MODName type (parameter values)

MODName is the name of the model for the device

type refers to type of device [ D:diode, NPN: npn bipolar transistor, PNP: pnp

bipolar transistor, NMOS: nmos transistor, PMOS: pmos transistor, NJF: N-

channel JFET model, PJF: P-channel JFET model]

parameter values specify the device characterstics.

DIODE

Element line: Dname +node –node MODName

Model Statement: .MODEL MODName D<parameter values>


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Example:

D1 2 1 DIODE

.MODEL DIODE D(IS=4.7E-12,N=1)

BIPOLAR TRANSISTORS

Element line: Qname Collectornode Basenode Emitternode BJT_modelName

Model Statement: .MODEL BJT_modelName NPN<parameter values>


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Example:

Q1 3 2 1 NPN

.MODEL NPN NPN(BF=200 CJC=20pf CJE=20pf

MOSFETS

Element line: Mname Drainnode Gatenode Sourcenode bulknode ModelName L=

W=

Model Statement: .MODEL ModelName NMOS<parameter values>


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Example:

M1 10 20 0 0 NFET

.MODEL NFET NMOS (LEVEL=0 VTO=2 KP=0.1)


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JFETS

Element line: Jname Drainnode Gatenode Sourcenode ModelName

Model Statement: .MODEL ModelName NJF/PJF<parameter values>

1.3.6 Command or Control Statements to Specify the Type of

Analysis

.OP Statement: This statement instructs Spice to compute the DC

operating point:

Voltages at the nodes

Current in each voltage source

Operating point of each element

Syntax:

.OP

.DC Statement: This is a method of varying a parameter over a range of

values so that we get a batch of cases solved all at once. A DC sweep is

made by changing the values of a source. The syntax for DC sweep is

.DC Sweep_Variable Starting_Value Stopping_Value Increment

Example:

.DC Vs 20.0 40.0 1.0

.AC Statement: .AC command was designed to make a sweep of many

frequencies for a given circuit. This is called a frequency response . Three

types of ranges are possible for the frequency sweep: LIN, DEC and OCT.

.AC type #points start stop

.AC LIN 1 60Hz 60Hz; <== single frequency.

.AC LIN 11 100 200; <== a linear range frequency sweep using

*frequencies of 100Hz, 110Hz, 120Hz, 130Hz, 140Hz, 150Hz, 160Hz,

170Hz, *180Hz, 190Hz and 200Hz.

.AC DEC 20 1Hz 10kHz; <== a logarithmic range(base 10) sweep

using 20 points *per decade over a range of four decades.

.AC OCT 20 1Hz 800Hz; ; <== a logarithmic range(base 2) sweep

using *20 points per octave over a range of ten octaves.


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.TF Statement: This statement instructs Spice to compute small signal

characteristics.

The ratio of output to input variable(gain and transfer gain)

The resistance with respect to input source.

The resistance with output source

.TF outvar inscr

Outvar: output variable

Inscr: input source

Example:

.TF V(3,0) vin

.SENS Statement: This instructs PSpice to calculate the DC small signal

sensitivities of each specified output variable with respect to every circuit

parameter.

.SENS VARIABLE

Example: .SENS V(3,0)

.TRAN Statement: This statement specifies the time interval over which

the transient analyses take place, and the time increments. The format is

as follows:

.TRAN TSTEP TSTOP <TSTART <TMAX>> <UIC>

TSTEP is the printing increment.

TSTOP is the final time.

TSTART is the starting time (If omitted, TSTART is assumed to be zero)

TMAX is the maximum step size.

UIC stands for Use Initial Conditions and instructs PSpice not to do the

quiescent operating point before beginning the transient analysis. If UIC is

specified. PSPICE will use the initial conditions specified in the element

statements.

.IC Statement: This statement provides an alternate way to specify initial

conditions of nodes.

.IC Vnode1=value Vnode=value

.PROBE Statement: PSpice will create a file named ".DAT" holding the

data as well as the usual ".OUT" file with basic information about the

circuit.

PROBE V(5,23) I(Rx) I(L4)

The above statement tells PSpice to save only the voltage drop between

nodes 5 and 23, the current through resistor, Rx, and the current through

inductor, L4, all in binary format. No other data will be saved.

1.3.7 Output Statements

These statements will instruct PSpice what output to generate. If you do not

specify an output statement. PSpice will always calculate the DC operating

points. The two types of outputs are the print and plot. A print is a plot of data

points and a plot is a graphical representation. The .PRINT TYPE OV OV OV …. .PLOT TYPE OV OV OV ….


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in which TYPE specifies the type of analysis to be printed or plotted and can be :

DC

TRAN

AC

The output variables are OV1, OV2 and can be voltage or currents in voltage

sources. Node voltages and device currents can be specified as magnitude(M),

phase(P), real(R) or imaginary(I) parts by adding the suffix to V or I as follows:

M: magnitude

DB: magnitude in dB(decibels)

P: phase

R: real part

I: imaginary part

Examples:

.PRINT DC I(Ra) ; prints the currents from + to - of Ra

.PRINT DC I(Rb) I(Rc) ; prints the currents through Rb and Rc

.PRINT DC V(1) V(2) V(3) ; prints the node voltages

.PRINT DC V(1,2) ; prints the voltage across Ra

.PRINT DC V(3,2) ; prints the voltage across Is

.PRINT DC V(1,2) I(Ra) ; voltage and current for Ra

.PRINT DC V(2,0) I(Rb) ; V(2,0) same as V(2)

.PRINT AC VM(30,9) VP(30,9); magnitude & angle of voltage

.PRINT AC IR(Rx) II(Rx); real & imag. parts Rx current

.PLOT AC VM(17) VP(17) VR(17) VI(17); the whole works on node 17

1.3.8 RUNNING SPICE AND VIEWING OUTPUT

1. On the computer's Desktop screen, click on Start, move the cursor

to Programs > Orcad 16.0 >PSpice AD demo

2. The Orcad PSpice A/D demo should open. Click on File > New

>Text file

3. The New Pspice A/D demo-[Text1] opens.

4. Type the netlist and once completed, click on file > save. The save as window opens, browse for the folder you want to save and save the file with name of file .CIR extension. Click save and close the window.

5. Next click file > close. Then file > Open Simulation. A window open simulation pop up. Browse for file saved in step [ name of file.CIR ]. Double click on the .CIR file you want to simulate. 6. Click Simulation > Run name of file. A window Analysis type pop

up select any analysis [AC/DC/Transient].


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7. Name of file- Pspice A/D Demo- [name of file (active ] window will appear. Then click > trace> add trace. Add traces window pop

ups write the trace expression and view output plot.

8. The files to be observed are

Click view > output file ; The printed output will be

available

Click view > dock output window and simulation status window Check both the windows . In output window you can observe analysis time, watch variables, no. of devices. In

simulation status window you observe any errors which

you edit in view > circuit file make the changes in netlist.

1.4 ANALYSIS BY USING SCHEMATIC FILE EDITOR

INTRODUCTION

This tutorial will introduce Orcad PSPICE. It will take you through the steps of

entering a schematic diagram, specifying the type of analysis, running the

simulation, and viewing the output file. The Orcad PSPICE software allows the

user to input their circuits using a schematic capture program (called "Capture" or Capture CIS . The software creates a SPICE input file from this diagram and performs the analysis. In this course, we will utilize the Capture program.

Starting a New PSPICE File

To learn the fundamental steps of running a PSPICE simulation we will begin

with the simple resistive circuit shown in figure 1.

1. On the computer's Desktop screen, click on Start, move the cursor to all

Programs > Orcad 16.0 demo >Orcad Capture CIS demo

2. The Orcad Capture window should open. Click on File > New > Project..

3. The New Project dialog box should open.

4. Type the name of your circuit in the "Name" box, and indicate the path to

the directory in which you want to store your file under "Location".

5. Click on the radio button next to: Analog or Mixed A/D, then click OK.

6. The Create PSPICE Project dialog box will appear. Select "Create a blank

project", and click OK.

7. A schematic entry window will appear. The screen should now look

similar to that in Figure


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Figure 2. Schematic Entry Window

Figure 3. Place Part Dialog Box


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Placing the Parts 1. Select Place > Part. The place part dialog box will open as shown in figure

3 (again, it may have a different appearance). In the lower left-hand

corner a list of the libraries that have been loaded will appear. Your list

may be different that the one shown in the figure. If this is the first time

you are running PSPICE on a particular computer all of the libraries may

not appear. At a minimum you should install the libraries: analog, eval,

source, and special. To add a Library, click on the Add Library Icon (a

small square above the library list in version 16.2). The libraries listed

above can be found in the following directory:

../tools/capture/library/pspice/demo (or something similar)

Add each of the four libraries listed above.

2. In the Place Part dialog box, click on the "Analog" library, then click on

the "R" in the Part List. A drawing of a resistor should appear in the lower

right corner. Press Enter/Return.

3. Move your mouse pointer over the schematic window. A resistor should

be following the pointer. Drag the resistor to the desired location and

click once to place it.

4. Drag to the next location to place the second resistor and click to place it.

5. Since we want the third resistor to be vertical, right-click the mouse

button and select "Rotate" from the popup menu. Then click to place the

third resistor (see figure 4).

Figure 4. Resistor Placement


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6. Once all of the resistors have been placed, right-click the mouse button

and select "End Mode" from the pop-up menu. This will cause the resistor

to disappear. Alternatively, you may enter ESC . 7. Next, we need to add the DC voltage source. Select the "Source" library

from the Place Part window and the part "VDC." Place this on the

schematic as you did with the resistors.

8. Every circuit that is simulated on PSPICE must have a ground node

indicated. This is done by entering the ground symbol. To place the

ground, select Place>Ground (or click on the ground symbol on the

toolbar). Select the "Source" library and the ground part labeled "0". It is

very important that you use this particular ground or your

simulation will not run. The first time you use this ground you may need

to add the Source library from the Place Ground window. Place the

ground as shown in figure 5.

Figure 5. Circuit Element Placement

Wiring the schematic 1. Select the Place Wire button from the toolbar.

2. Drag the cross-hair pointer to the positive end of the VDC source. Click

on it.

3. Move the cross-hair pointer to the left terminal marker of the first

resistor. Click on it.

4. Repeat the procedure until all components are connected.

5. Click the right mouse button. Select End Wire and click on it. Your

schematic should now appear as the one in figure 6.


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Figure 6. Wired Circuit

Setting the component values 1. All of the resistor values default to KΩ. To change a resistor value,

double click on the resistor value. The Display Properties box appears.

2. In the Value box, type in the desired resistance. Make sure to use the

appropriate suffix as listed in the PSPICE introduction. Click on OK.

3. Repeat for all resistors.

4. Using the same procedure change the value of the dc voltage source to

10V. The circuit should now appear as the one in figure 7.

Figure 7. Circuit with Component Values


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Specifying the type of analysis 1. In this simple DC circuit there are no time varying voltages or currents.

Thus, we only need to find the values of the dc voltages and currents

throughout the circuit. This is referred to as a DC Bias analysis.

2. Choose the menu option: PSPICE a New Simulation Profile. A dialog

box will open. Type in the name of the simulation as "DC Bias". Click

Create.

3. The Simulations Settings dialog box opens. Under Analysis Type, select

Bias Point and click OK.

4. Save your circuit.

Running the Simulation 1. Select the menu option: PSPICE >Run. The simulation will run and the

simulation window will open as shown in figure 8.

2. In the lower left corner of the window is an output text section that

displays the progress of the simulation and any errors that were

encountered.

3. In this example, we will view the results of the simulation as a SPICE

output file. Select the menu option: View >Output File. A text file will

appear in the upper window. Figure 9 shows the output and describes

each section. Note that the default output includes the voltage at each

node and the current flowing through each voltage source. For example,

the initial circuit listing in the output shows us that the 3K resistor is

connected between nodes N00132 and N00159. The output indicates that

the voltages at those two nodes are 8 and 5 volts respectively. Thus, this

resistor has 3 volts across it.

Figure 8. Simulation Window


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**** 03/29/01 13:17:18 ************** PSpice Lite (Mar 2000) ***************** ** Profile: "SCHEMATIC1-dc bias" [ C:\Program Files\OrcadLite\project1-SCHEMATIC1-dc

bias.sim ]

**** CIRCUIT DESCRIPTION

******************************************************************************

** Creating circuit file "project1-SCHEMATIC1-dc bias.sim.cir"

** WARNING: THIS AUTOMATICALLY GENERATED FILE MAY BE OVERWRITTEN BY

SUBSEQUENT

SIMULATIONS

*Libraries:

* Local Libraries :

* From [PSPICE NETLIST] section of C:\Program Files\OrcadLite\PSpice\PSpice.ini file:

.lib "nom.lib"

*Analysis directives:

.PROBE V(*) I(*) W(*) D(*) NOISE(*)

.INC ".\project1-SCHEMATIC1.net"

**** INCLUDING project1-SCHEMATIC1.net ****

* source PROJECT1

R_R1 N00102 N00132 2K

R_R2 N00132 N00159 3K

R_R3 0 N00159 5K

V_V1 N00102 0 10V

**** RESUMING "project1-SCHEMATIC1-dc bias.sim.cir" ****

.END

**** 03/29/01 13:17:18 ************** PSpice Lite (Mar 2000) *****************

** Profile: "SCHEMATIC1-dc bias" [ C:\Program Files\OrcadLite\project1-SCHEMATIC1-dc

bias.sim ]

**** SMALL SIGNAL BIAS SOLUTION TEMPERATURE = 27.000 DEG C

******************************************************************************

NODE VOLTAGE NODE VOLTAGE NODE VOLTAGE NODE VOLTAGE

(N00102) 10.0000 (N00132) 8.0000 (N00159) 5.0000

VOLTAGE SOURCE CURRENTS

NAME CURRENT

V_V1 -1.000E-03

TOTAL POWER DISSIPATION 1.00E-02 WATTS

JOB CONCLUDED

TOTAL JOB TIME .13

Figure 9. PSPICE Output File

4. Return to the window with your schematic. Select PSPICE > Bias Points>

Enable Bias>Voltage Display (if it is not already selected). The dc bias

voltages will now be displayed directly on your diagram eliminating the

need to view the output file at all. See figure 10. Experiment with

displaying the current and power values.

Current Sources

A DC independent current source can be found in the parts list as IDC. This is

similar to the voltage source used above except the current is held at a

specified value.


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Figure 10. Schematic with Bias Voltage Display

Displaying Currents and Power In addition to displaying voltages, current and power values found in the bias

point analysis can also be displayed. Enter the schematic shown in Figure 11.

Perform the DC bias point analysis. Select PSPICE> Bias Points >Enable Bias

Power Display . Confirm that the power values displayed are correct.

Figure 11. DC Analysis Problem


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EXPERIMENT 1.A

COMMON EMITTER AMPLIFIER (SOFTWARE)

AIM

1. To simulate the Common Emitter amplifier in Pspice and study the

transient and frequency response. 2. To determine the phase relationship between the input and output

voltages by performing the transient analysis. 3. To determine the maximum absolute gain, maximum gain in dB, 3dB gain,

lower and upper cutoff frequencies and bandwidth of CE amplifier by

performing the AC analysis.

SOFTWARE TOOL

1. LAN connected computer systems with WINDOWS XP

2. PC loaded with Orcade 16.0 PSpice software.

THEORY

The Common-Emitter (CE) is the most frequently used configuration in practical

amplifier circuits, since it provides good voltage, current, and power gain. The

input to the CE is applied to the base-emitter circuit and the output is taken from

the collector-emitter circuit, making the emitter the terminal "common" to both

input and output. The CE is set apart from the other configurations, because it is

the only configuration that provides a phase reversal between input and output

signals.

When positive half of the signal is applied, the voltage between base and emitter

(Vbe) is increased because it is already positive with respect to ground. So

forward bias is increased i.e., the base current is increased. Due to transistor

action, the collector current IC is increased β times. When this current flows through RC, the drop IC RC increases considerably. As a consequence of this, the

voltage between collector and emitter (Vce) decreases. In this way, amplified

voltage appears across RC. Therefore the positive going input signal appears as a

negative going output signal i.e., there is a phase shift of 180° between the input

and output.

The gain from the base to the collector can be approximated by the collector

resistance over the emitter resistance (RC’/RE).where RC’ is the AC resistance seen by the collector, RC|| RL, and RE’ is the AC resistance seen by the emitter, RE.

The emitter resistance controls the DC bias. The gain can be increased by

choosing a smaller RE.


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CIRCUIT DIAGRAM

CIRCUIT FILE


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PROCEDURE

1. SCHEMATIC i) Select the components from the symbol library and place it on

the schematic window.

ii) The selected symbol is displayed on the screen in red. Move the symbol to the desired location using the mouse.

iii) You can change the view of most symbols by performing the following operations: rotate, mirror and flip.

iv) Wires and junctions are used to wire together parts and indicate electrical connections.

v) To draw a wire, select the Wire menu command, Move the cursor to the wire starting position and click the left mouse button or press Enter. Now you can move the other end of wire to the desired location.

vi) The junction symbol (a large dot) indicates an electrical connection between wires or between a wire and a part pin.

vii) Most parts (components) require that you specify the following set of attributes: reference name, value or model name, and optional parameters.

viii) You can also change the attributes by double-clicking on a part on the schematic.

ix) Once circuit construction is completed; the analysis is to be

performed.

x) To simulate a circuit, select the Analysis|Run Simulation menu command from the Schematic.

xi) If there are any errors during the simulation, the simulator writes any applicable error messages to the simulation output file.

xii) Three different modes of circuit analysis: DC, AC (frequency response) and transient.

xiii) Before simulation, we have to do the analysis setup.

xiv) Once analysis setup is over, then perform Run Simulation.

xv) From the analysis note down the readings, plot the graph, do

the calculations.

2. CIRCUIT FILE

i) The SPICE circuit file (default filename extension ".CIR") is the input file for the simulator program.

ii) This is a text file, which contains the circuit netlist, simulation command and device model statements.


25

iii) Write the circuit file for the given schematic assuming the node numbers. Save the circuit file.

iv) To simulate the circuit file, select the Analysis|Run Simulation menu command from the circuit file menu.

v) If there are any errors during the simulation, the simulator writes any applicable error messages to the simulation output file.

vi) Three different modes of circuit analysis: DC, AC (frequency response) and transient.

vii) Before simulation, we have to do the analysis setup.

viii) Once analysis setup is over, then perform Run Simulation.

ix) From the analysis note down the readings, plot the graph, do

the calculations.

EXPECTED GRAPHS

1. TRANSIENT RESPONSE


26

2. FREQUENCE RESPONSE

RESULT

1. From the transient analysis the phase relationship between input and output

voltage signals is ___________ degrees.

2. From the frequency response curve the following results are calculated:

S. No. Parameter Value

1 Max. Absolute Gain

2 Max. Gain in dB

3 3dB Gain

4 Lower Cutoff Frequency

5 Upper Cutoff Frequency

6 Bandwidth


27

EXPERIMENT 1.B

COMMON EMITTER AMPLIFIER (HARDWARE)

AIM

1. Plot the frequency response of a BJT amplifier in common emitter

configuration.

2. Calculate gain. 3. Calculate bandwidth

HARDWARE REQUIRED

S.No. Component Range/Rating Quantity

1. Regulated DC Power

Supply

12 V 1

2. Function Generator 0.1Hz-1MHz 1

3. CRO 0-20MHz 1

4. BJT BC107(npn) 1

5. Resistors KΩ 2 KΩ 2 . KΩ, KΩ 1

6. Capacitors 10µF 2

100 µF 1

7. Connecting Wires 22/24 AWG 4

CIRCUIT DIAGRAM


28

PROCEDURE

1. Connect the circuit diagram as shown in figure for common emitter

amplifier on breadboard.

2. Adjust input signal amplitude in the function generator and observe an

amplified voltage at the output without distortion.

3. By keeping input signal voltage, say at 50mV, vary the input signal

frequency from 0 to 1MHz in steps as shown in tabular column and note the

corresponding output voltages.

4. Find the voltage gain, 𝐴𝑉 = 20log 𝑉𝑉𝑖

5. Plot AV VS frequency on a semi-log sheet.

OBSERVATION TABLE Vin= 50mV

Frequency (Hz) Output Voltage(Vo) Gain Av=Vo/Vi Gain(dB)=20log10(Vo/Vi)

10 20

900K 1M

EXPECTED GRAPH

RESULT

1. Frequency response of common emitter BJT amplifier is plotted.

2. Gain = _______dB (maximum).

3. Bandwidth, f2—f1 = _________Hz. VIVA VOCE

1. Why the CE amplifier provides a phase reversal?

2. In the dc equivalent circuit of an amplifier, how are capacitors treated?

3. What is the effect of bypass capacitor on frequency response?

4. Define lower and upper cutoff frequencies for an amplifier.

5. State the reason for fall in gain at low and high frequencies.

6. What is meant by unity gain frequency?

7. Define Bel and Decibel.

8. What do we represent gain in decibels?

9. Why do you plot the frequency response curve on a semi-log paper?


29

EXPERIMENT 2.A

COMMON BASE AMPLIFIER (SOFTWARE)

AIM

1. To simulate the Common Base amplifier in Pspice and study the transient

and frequency response.

2. To determine the phase relationship between the input and output

voltages by performing the transient analysis.

3. To determine the maximum absolute gain, maximum gain in dB, 3dB gain,

lower and upper cutoff frequencies and bandwidth of CB amplifier by

performing the AC analysis.

SOFTWARE TOOL



THEORY

The common base transistor amplifier finds applications where low input

impedance is required. The common base format is probably most commonly

used for RF applications, where its input impedance can be used for matching to

the low source impedances often found in this arena.

For both NPN and PNP circuits, it can be seen that for the common base amplifier

circuit, the input is applied to the emitter, and the output is taken from the

collector. The common terminal for both circuits is the base. The common base

amplifier configuration is not used as widely as transistor amplifier

configurations. However it does find uses with amplifiers that require low input

impedance levels. One application is for moving-coil microphones preamplifiers -

these microphones have very low impedance levels. Another application is

within VHF and UHF RF amplifiers where the low input impedance allows

accurate matching to the feeder impedance which is typically Ω or Ω. It is worth noting that the current gain of a common-base amplifier is always less

than unity. However the voltage gain may be more, but it is a function of input

and output resistances (and also the internal resistance of the emitter-base

junction). As a result, the voltage gain of a common-base amplifier can be very

high.


30

CIRCUIT DIAGRAM

CIRCUIT FILE


31

PROCEDURE

Procedure is same as that of Experiment 1.A

EXPECTED GRAPHS




32

RESULT






2 Max. Gain in dB

3 3dB Gain



6 Bandwidth


33

EXPERIMENT 2.B

COMMON BASE AMPLIFIER (HARDWARE)

AIM

1. Plot the frequency response of a BJT amplifier in common base

configuration.


HARDWARE REQUIRED



Supply

12 V 1


3. CRO 0-20MHz 1

4. BJT BC107NPN) 1

5. Resistors 10KΩ 2 KΩ, . KΩ, KΩ 1


100 µF 1


CIRCUIT DIAGRAM


34

PROCEDURE

1. Connect the circuit diagram as shown in figure for common base amplifier

on breadboard.










10 20

900K 1M

EXPECTED GRAPH

RESULT

1. Frequency response of common base BJT amplifier is plotted.


3. Bandwidth, f2—f1 = _________Hz. VIVA VOCE

1. What is the typical value of the current gain of a common-base

configuration?

2. What is the range of the input impedance of a common-base

configuration?

3. In a common-base amplifier, the input signal is applied between which

terminals?

4. What is the controlling current in a common-base configuration?


35

EXPERIMENT 3.A

COMMON SOURCE AMPLIFIER (SOFTWARE)

AIM

1. To simulate the Common Source amplifier in Pspice and study the

transient and frequency response.



3. To determine the maximum absolute gain, maximum gain in dB,

3dB gain, lower and upper cutoff frequencies and bandwidth of CS

amplifier by performing the AC analysis.

SOFTWARE TOOL



THEORY

In Common Source Amplifier Circuit Source terminal is common to both the

input and output terminals. In this Circuit input is applied between Gate and

Source and the output is taken from Drain and the source. JFET amplifiers

provide an excellent voltage gain with the added advantage of high input

impedance and other characteristics JFETs are often preferred over BJTs for

certain types of applications. The CS amplifier of JFET is analogous to CE

amplifier of BJT.

The FET has some advantages and some disadvantages relative to the bipolar

transistor. Field-effect transistors are preferred for weak-signal work, for

example in wireless, communications and broadcast receivers. They are also

preferred in circuits and systems requiring high impedance. The FET is not, in

general, used for high-power amplification, such as is required in large wireless

communications and broadcast transmitters.

Field-effect transistors are fabricated onto silicon integrated circuit (IC) chips. A

single IC can contain many thousands of FETs, along with other components such

as resistors, capacitors, and diodes.


36

CIRCUIT DIAGRAM

CIRCUIT FILE


37

PROCEDURE


EXPECTED GRAPHS




38

RESULT






2 Max. Gain in dB

3 3dB Gain



6 Bandwidth


39

EXPERIMENT 3.B

COMMON SOURCE AMPLIFIER (HARDWARE)

AIM

1. Plot the frequency response of a JFET amplifier in common source

configuration.


HARDWARE REQUIRED



Supply

12 V 1


3. CRO 0-20MHz 1

4. JFET BFW10/11(N CHANNEL) 1

5. Resistors KΩ, . KΩ, . KΩ, KΩ 1


100 µF 1


CIRCUIT DIAGRAM


40

PROCEDURE

1. Connect the circuit diagram as shown in figure for common source





frequency from 0 to 1MHz in steps as shown in tabular column and note

the corresponding output voltages.





10 20

900K 1M

EXPECTED GRAPH

RESULT

1. Frequency response of common source JFET amplifier is plotted.


3. Bandwidth, f2—f1 = _________Hz.

VIVA VOCE

1. What is Miller effect on common source amplifier?

2. What is the purpose of source resistor and gate resistor?

3. What is swamping resistor?

4. What is the purpose of swamping resistor in common source amplifier?

5. FET is a liner or non-linear device. And justify your answer

6. What is square law and give an example for a square law device?


41

EXPERIMENT 4.A

TWO STAGE RC COUPLED AMPLIFIER (SOFTWARE)

AIM

1. To simulate the two stage RC coupled amplifier in Pspice and study the





lower and upper cutoff frequencies and bandwidth the two stage RC coupled


SOFTWARE TOOL 1. LAN connected computer system with WINDOWS XP

2. PC loaded with Orcade 16.0 Pspice software

THEORY

An amplifier is the basic building block of most electronic systems. Just as one

brick does not make a house, a single-stage amplifier is not sufficient to build a

practical electronic system. The gain of the single stage is not sufficient for

practical applications. The voltage level of a signal can be raised to the desired

level if we use more than one stage. When a number of amplifier stages are used

in succession (one after the other) it is called a multistage amplifier or a cascade

amplifier. Much higher gains can be obtained from the multi-stage amplifiers.

In a multi-stage amplifier, the output of one stage makes the input of the next

stage. We must use a suitable coupling network between two stages so that a

minimum loss of voltage occurs when the signal passes through this network to

the next stage. Also, the dc voltage at the output of one stage should not be

permitted to go to the input of the next. If it does, the biasing conditions of the

next stage are disturbed.

Figure shows how to couple two stages of amplifiers using RC coupling scheme.

This is the most widely used method. In this scheme, the signal developed across

the collector resistor RC of the first stage is coupled to the base of the second

stage through the capacitor CC. The coupling capacitor blocks the dc voltage of

the first stage from reaching the base of the second stage. In this way, the dc

biasing of the next stage is not interfered with. For this reason, the capacitor CC is

also called a blocking capacitor. As the number of stages increases, the gain

increases and the bandwidth decreases. RC coupling scheme finds applications in

almost all audio small-signal amplifiers used in record players, tape recorders,

public-address systems, radio receivers, television receivers, etc.


42

CIRCUIT DIAGRAM

CIRCUIT FILE


43

PROCEDURE


EXPECTED GRAPHS

1. TRANSIENT ANALYSIS

2. FREQUENCY RESPONSE


44

RESULT

1. From the transient analysis, it is observed that,___________________________




2 Max. Gain in dB

3 3dB Gain



6 Bandwidth

3. From the AC response, it is observed that, ________________________


45

EXPERIMENT 4.B

TWO STAGE RC COUPLED AMPLIFIER (HARDWARE)

AIM

1. Plot the frequency response of a two stage RC coupled amplifier.


HARDWARE REQUIRED



Supply

12 V 1


3. CRO 0-20MHz 1

4. BJT BC107(NPN) 2

5. Resistors KΩ 5 . KΩ, KΩ, KΩ 2 KΩ 1


100 µF 2


CIRCUIT DIAGRAM


46

PROCEDURE

1. Connect the circuit diagram as shown in figure for two stage RC coupled











10 20

900K 1M

EXPECTED GRAPH

RESULT

1. Frequency response of two stage RC amplifier is plotted.


3. Bandwidth, fH--fL = _________Hz. VIVA VOCE

1. Why do you need more than one stage of amplifiers in practical circuits?

2. What is the effect of cascading on gain and bandwidth?

3. What happens to the 3dB frequencies if the number of stages of amplifiers

increases?

4. Why we use a logarithmic scale to denote voltage or power gains, instead

of using the simpler linear scale?

5. What is loading effect in multistage amplifiers?


47

EXPERIMENT 5.A

CURRENT SHUNT FEEDBACK AMPLIFIER (SOFTWARE)

AIM

1. To simulate the Current shunt feedback amplifier in Pspice and study the





lower and upper cutoff frequencies and bandwidth of the current shunt

feedback amplifier by performing the AC analysis.



THEORY

Feedback plays a very important role in electronic circuits and the basic

parameters, such as input impedance, output impedance, current and voltage

gain and bandwidth, may be altered considerably by the use of feedback for a

given amplifier. A portion of the output signal is taken from the output of the

amplifier and is combined with the normal input signal and thereby the feedback

is accomplished.

There are two types of feedback. They are i) Positive feedback and ii) Negative

feedback. Negative feedback helps to increase the bandwidth, decrease gain,

distortion, and noise, modify input and output resistances as desired. A current

shunt feedback amplifier circuit is illustrated in the figure. It is called a series-

derived, shunt-fed feedback. The shunt connection at the input reduces the input

resistance and the series connection at the output increases the output

resistance. This is a true current amplifier.


48

CIRCUIT DIAGRAM

CIRCUIT FILE


49

PROCEDURE


EXPECTED GRAPHS



50


RESULT





2 Max. Gain in dB

3 3dB Gain



6 Bandwidth


51

EXPERIMENT 5.B

CURRENT SHUNT FEEDBACK AMPLIFIER (HARDWARE)

AIM

1. Plot the frequency response of Current shunt feedback amplifier.

2. Calculate gain. 3. Calculate bandwidth.

HARDWARE REQUIRED



Supply

12 V 1


3. CRO 0-20MHz 1

4. BJT BC107(NPN) 2

5. Resistors KΩ 5 . KΩ, KΩ, KΩ 2 . KΩ , KΩ 1


100 µF 2


CIRCUIT DIAGRAM


52

PROCEDURE

1. Connect the circuit diagram as shown in figure for Current shunt feedback











10 20

900K 1M

EXPECTED GRAPH

RESULT

1. Frequency response of current shunt feedback amplifier is plotted.



1. State the merits and demerits of negative feedback in amplifiers.

2. If the bypass capacitor CE in an RC coupled amplifier becomes accidentally

open circuited, what happens to the gain of the amplifier? Explain.

3. When will a negative feedback amplifier circuit be unstable?

4. What is the parameter which does not change with feedback?

5. What type of feedback has been used in an emitter follower circuit?


53

EXPERIMENT 6.A

VOLTAGE SERIES FEEDBACK AMPLIFIER (SOFTWARE)

AIM

1. To simulate the Voltage series feedback amplifier in Pspice and study the





lower and upper cutoff frequencies and bandwidth of the Voltage series

feedback amplifier by performing the AC analysis.



THEORY

When any increase in the output signal results into the input in such a way as to

cause the decrease in the output signal, the amplifier is said to have negative

feedback. The advantages of providing negative feedback are that the transfer

gain of the amplifier with feedback can be stabilized against variations in the

hybrid parameters of the transistor or the parameters of the other active devices

used in the circuit. The most advantage of the negative feedback is that by proper

use of this, there is significant improvement in the frequency response and in the

linearity of the operation of the amplifier. This disadvantage of the negative

feedback is that the voltage gain is decreased.

The other name of voltage series feedback amplifier is shunt derived series fed

feedback amplifier. The fraction of output voltage is applied in series with input

voltage through feedback circuit. Feedback circuit shunt the output but in series

with input. So the output impedance is decreased while input impedance is

increased. The input & output impedance of an ideal voltage series feedback

amplifier is infinite & zero respectively. The resistor RE is used to provide

necessary biasing for the amplifier with voltage series feedback gain of the

amplifier decreases


54

CIRCUIT DIAGRAM

CIRCUIT FILE


55

PROCEDURE


EXPECTED GRAPHS




56

RESULT





2 Max. Gain in dB

3 3dB Gain



6 Bandwidth


57

EXPERIMENT 6.B

VOLTAGE SERIES FEEDBACK AMPLIFIER (HARDWARE)

AIM

1. Plot the frequency response of Voltage series feedback amplifier.

2. Calculate gain. 3. Calculate bandwidth.

HARDWARE REQUIRED



Supply

12 V 1


3. CRO 0-20MHz 1

4. BJT BC107(NPN) 2

5. Resistors KΩ , . KΩ, KΩ, KΩ 1



CIRCUIT DIAGRAM


58

PROCEDURE

1. Connect the circuit diagram as shown in figure for Voltage series feedback









PRECAUTIONS 1. Avoid loose connections give proper input voltage



10 20

900K 1M

EXPECTED GRAPH

RESULT

1. Frequency response of voltage series feedback amplifier is plotted.



1. What is the effect of negative feedback on voltage gain?

2. What is the value of negative feedback fraction?

3. When voltage feedback (negative) is applied to an amplifier, what

happens to its input impedance?

4. When current feedback (negative) is applied to an amplifier, what

happens to its input impedance? 5. What is the effect of negative voltage feedback on bandwidth?


59

EXPERIMENT 7.A

CASCODE AMPLIFIER (SOFTWARE)

AIM 1. To simulate the Cascode amplifier in Pspice and study the transient and

frequency response.

2. To determine the phase relationship between the input and output voltages by

performing the transient analysis.

3. To determine the maximum gain, 3dB gain, lower and upper cutoff frequencies

and bandwidth of cascode amplifier by performing the AC analysis.



THEORY Cascode amplifier is a two stage circuit consisting of a transconductance amplifier followed by a buffer amplifier. The word cascode was originated from the phrase cascade to cathode . This circuit have a lot of advantages over the single stage amplifier

like, better input output isolation, better gain, improved bandwidth, higher input

impedance, higher output impedance, better stability, higher slew rate etc. The reason

behind the increase in bandwidth is the reduction of Miller effect. Cascode amplifier

is generally constructed using FET ( field effect transistor) or BJT ( bipolar junction

transistor). One stage will be usually wired in common source/common emitter mode

and the other stage will be wired in common base/ common emitter mode.

CIRCUIT DIAGRAM


60

CIRCUIT FILE

PROCEDURE


EXPECTED GRAPHS



61


RESULT 1. From the transient analysis, it is observed that,___________________________




2 Max. Gain in dB

3 3dB Gain



6 Bandwidth


62

EXPERIMENT 7.B

CASCODE AMPLIFIER (HARDWARE)

AIM

1. Plot the frequency response of a cascode amplifier using JFET.


HARDWARE REQUIRED


1. Regulated DC

Power Supply

30 V 1

2. Function

Generator

0.1Hz-1MHz 1

3. CRO 0-20MHz 1

4. JFET BFW10/11(N CHANNEL) 2

5. Resistors KΩ, KΩ, KΩ, , . KΩ, KΩ 1 KΩ 2


100 µF 1


CIRCUIT DIAGRAM


63

PROCEDURE

1. Connect the circuit diagram as shown in figure for cascode amplifier on

breadboard.








PRECAUTIONS 1. Avoid loose connections give proper input voltage



10 20

900K 1M

EXPECTED GRAPH

RESULT

1. Frequency response of cascode amplifier is plotted.


3. Bandwidth, fH--fL = _________Hz.

VIVA VOCE 1. Why is cascode amplifier called as wide band amplifier?

2. What are the characteristics of cascode amplifier?


64

EXPERIMENT 8.A

RC PHASE SHIFT OSCILLATOR USING TRANSISTORS

(SOFTWARE)

AIM 1. To simulate the RC phase shift oscillator using transistors in Pspice.

2. To evaluate the frequency of oscillations of oscillator and compare with

that of the theoretical value.

SOFTWARE TOOL

1. LAN connected computer system with WINDOWS XP


THEORY

Any circuit which is used to generate an ac voltage without an ac input signal is

called an oscillator. Positive feedback is used in oscillators. Based on the type of

components used, the oscillators are classified in to two types. They are LC

oscillators and RC oscillators. In the RC phase shift oscillator the required phase

shift of 180° in the feedback loop from output to input is obtained by using R and

C components. Figure shows the circuit of RC phase shift oscillator using

cascaded connection of high pass filter. Here, a common emitter amplifier is

followed by three sections of RC phase shift network, the output of the last section being returned to the input.The phase shift, φ, given by each RC section is φ=tan-1 /ωRC .If R is made zero φ will become °. But making R= is impracticable because if R is zero, then the voltage across it will become zero. Therefore, in practice the value of R is adjusted such that φ becomes °.

If the values of R and C are so chosen that, for the given frequency fr, the

phase shift of each RC section is 60°. Thus such a RC ladder network produces a

total phase shift of 180° between its input and output voltages for the given

frequency. Therefore, at the specific frequency fr, the total phase shift from the

base of the transistor around the circuit and back to the base will be exactly 360°

or 0°, the thereby satisfying Barkhausen condition for oscillation. The frequency

of oscillation is given by 𝑓𝑟 = 𝜋𝑅𝐶√6

At this frequency, it is found that the feedback factor of the network is |β|

= 1/29. In order that |Aβ| shall not be less than unity, it is required that the

amplifier gain |A| must be more than 29 for oscillator operation.


65

CIRCUIT DIAGRAM

CIRCUIT FILE


66

PROCEDURE


EXPECTED GRAPHS

TRANSIENT ANALYSIS

RESULT

The theoretical and practical calculation of the frequency of oscillation of

RC phase shift oscillator is calculated as follows:

Theoritical calculations Practical Calculations R=10K C=0.01 u 𝑓𝑟 = πRC√ + k

Where k=RC/R= fr=___________________Hz

T=______________mS f=1/T=________________Hz


67

EXPERIMENT 8.B

RC PHASE SHIFT OSCILLATOR USING TRANSISTORS

(HARDWARE) AIM

To measure the frequency of oscillation of RC phase shift oscillator and compare

with that of the theoretical value.

HARDWARE REQUIRED


1. Regulated DC

Power Supply

30 V 1

2. CRO 0-20MHz 1

3. BJT BC107(NPN) 1

4. Resistors KΩ, KΩ, . KΩ 1 KΩ 4

5. Capacitors 0.1µF 3

0.047µF 1

10 µF 1


CIRCUIT DIAGRAM


68

PROCEDURE

1. Connect the circuit diagram as shown in figure for RC phase shift oscillator

on breadboard.

2. Connect the output of the circuit to the Channel 1 of the CRO using BNC

Probe.

3. Note down the amplitude and time period of the output waveform.

4. Calculate the theoretical frequency of oscillations by using the

formula f = / πRC√6

5. Calculate the practical frequency of oscillations.

EXPECTED WAVEFORM

OBSERVATION TABLE Theoritical calculations Practical Calculations

R=10K C=0.01 u 𝑓𝑟 = πRC√ + k

Where k=RC/R= fr=___________________Hz

T=______________mS f=1/T=________________Hz

RESULT 1. Time period T of the ac signal available at the output = _____________s. 2. The frequency of oscillations, f= ________________________Hz

VIVA VOCE 1. What is Barkhausen criterion?

2. What is the maximum phase shift provided by the single RC network?

3. What is the condition of phase shift oscillator to produce sustained

oscillations?

4. Where does the starting voltage for an oscillator?

5. Why are RC oscillators preferred for the generation of low frequencies?

6. If the percentage feedback for sustained oscillations in an oscillator is 5%,

what is the required gain of amplifier?

7. Find the percentage feedback to produce sustained oscillators if amplifier

gain is 60.

8. An RC phase shift oscillator circuit has 3 identical RC networks with R= Ω, C= µF. Find the frequency of oscillation.


69

EXPERIMENT 9.A

SINGLE TUNED VOLTAGE AMPLIFIER (SOFTWARE)

AIM

1. To simulate the Single tuned voltage amplifier in Pspice and study the

transient and frequency response. 2. To determine the phase relationship between the input and output

voltages by performing the transient analysis. 3. To determine the maximum absolute gain, maximum gain in dB, 3dB gain,

lower and upper cutoff frequencies and bandwidth of Single tuned voltage


SOFTWARE TOOL



THEORY

A tuned amplifier is an electronic amplifier which includes bandpass filtering

components within the amplifier circuitry. They are widely used in all kinds of

wireless applications. The signal to be amplified is applied between the terminals

base and emitter. The tank circuit is tuned (i.e L or C may be varied) in such a

way that the resonant frequency becomes equal to the frequency of the input

signal. At resonance the tuned circuit offers very high impedance and thus, the

given input signal is amplified by the amplifier and appears with large value

across it and other frequencies will be rejected. So the tuned circuit selects the

derived frequency and rejects all other frequencies.

CIRCUIT DIAGRAM

https://en.wikipedia.org/wiki/Electronic_amplifier

https://en.wikipedia.org/wiki/Bandpass


70

CIRCUIT FILE

PROCEDURE


EXPECTED GRAPHS



71


RESULT






2 Max. Gain in dB

3 3dB Gain



6 Bandwidth


72

EXPERIMENT 9.B

SINGLE TUNED VOLTAGE AMPLIFIER (HARDWARE)

AIM

1. Plot the frequency response of a Single tuned voltage amplifier


HARDWARE REQUIRED



Supply

12 V 1


3. CRO 0-20MHz 1

4. BJT BC107(npn) 1

5. Resistors KΩ, KΩ, . KΩ, KΩ 1


100 µF,1nF 1

7. Inductors 1|mH 1


CIRCUIT DIAGRAM


73

PROCEDURE

1. Connect the circuit diagram as shown in figure for Single tuned voltage











10 20

900K 1M

EXPECTED GRAPH

RESULT

1. Frequency response of single tuned voltage amplifier amplifier is plotted.


3. Bandwidth, f2—f1 = _________Hz.

VIVA VOCE

1. What is a tuned amplifier

2. Define Q-factor

3. What is selectivity?

4. Is tuned amplifier a narrow band or wide band amplifier

5. Give the applications for tuned amplifier?

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