Project

A Mini Project Report on Wein’s Bridge Oscillator and Inverting Adder

Submitted By

K. Adiseshu BL.EN.U4ECE10089

Kiran T BL.EN.U4ECE10087

K. Srinivas Saketh BL.EN.U4ECE10086

Submitted To

G. Hemanth Kumar

DEPARTMENT OF ELECTRONICS AND COMMUNICATION

ECE 391 ELECTRONICS CIRCUITS LAB II

Wein’s Bridge Oscillator & Inverting Adder 1

ACKNOWLEDGEMENT

It is our pleasure to be indebted to various people, who directly or indirectly contributed in the

development of this project work and who influenced my thinking, behavior, and acts during

the course of study.

I express my sincere gratitude to Mr. G. Hemanth Kumar for providing us an opportunity to

undergo this project work.

I am thankful to my team mates and friends for their support, cooperation, and motivation

provided to me during the course of time for constant inspiration, presence.

Lastly, I would like to thank the almighty and my parents for their moral support and my

friends with whom I shared my day-to-day experience and received lots of suggestions

that improved my quality of work.


Contents

1. TINA

1.1 Introduction To TINA 4

1.2 Salient features of TINA 4

2. Wien’s Bridge Oscillator using IC741

2.1 Theory 8

2.2 Circuit Diagram 9

2.3 Design 9

2.4 Procedure 10

2.5 Applications 11

2.6 Advantages 12

2.7 Disadvantages 12

2.8 Output 12

3. Inverting Adder using IC741

3.1 Theory 13

3.2 Circuit Diagram 13

3.3 Design 13

3.4 Procedure 14

3.5 Applications 14

3.6 Output 15

4. Reference 16


1. TINA

1.1 Introduction:

TINA is a powerful application that allows you to test electronic circuits by creating them into a

virtual environment. You can use the program to design new circuits and add any component

with just a few clicks. The application can also perform tests and analyze the behavior of the

circuit under certain circumstances. You can use it to test a design without burning the fuses

from your lab.

TINA is an easy-to-use, powerful circuit simulation tool based on a SPICE engine. TINA-TI is a

fully functional version of TINA, loaded with a library of TI macro models plus passive and active

models.

1.2 Salient features of TINA:

TINA Design Suite is a powerful yet affordable circuit simulation and PCB design software

package for analyzing, designing, and real time testing of analog, digital, VHDL, MCU, and mixed

electronic circuits and their PCB layouts. You can also analyze SMPS, RF, communication, and

optoelectronic circuits; generate and debug MCU code using the integrated flowchart tool; and

test microcontroller applications in a mixed circuit environment. A unique feature of TINA is

that you can bring your circuit to life with the optional USB controlled TINALab

II andLogiXplorer hardware, which turns your computer into a powerful, multifunction T&M

instrument. Electrical engineers will find TINA an easy to use, high performance tool, while

educators will welcome its unique features for the training environment.

Super-fast multi-core engine: Every year, electronic circuits become faster and more complex,

and therefore require more and more computational power to analyze their operation. To meet

this requirement TINA v9 has the ability to utilize the increasingly popular scalable multi-thread

CPUs. Computers that incorporate dual or quad core CPUs can deliver up to 20-times faster

execution time for TINA's analysis engine compared to previous versions and main competitors.


http://www.tina.com/English/logixplorer

http://www.tina.com/English/tinalab

http://www.tina.com/English/tinalab

Easy to use schematic entry: Enter any circuit within minutes with TINA's easy-to-use schematic

editor. Enhance your schematics by adding text and graphics elements such lines, arcs arrows,

frames around the schematics and title blocks. Choose components from the large library

containing more than 20,000 manufacturer models. You can check schematics for errors with

TINA's advanced ERC functions. The schematic editor supports complex hierarchical designs,

team design and version control.

Powerful analysis tools: Analyze your circuit through more than 20 different analysis modes or

with 10 high tech virtual instruments. Present your results in TINA's sophisticated diagram

windows, on virtual instruments, or in the live interactive mode where you can even edit your

circuit during operation, develop, run, debug and test VHDL & MCU applications.

Design Tool: This powerful tool works with the design equations of your circuit to ensure that

the specified inputs result in the specified output response. The tool offers you a solution

engine that you can use to solve repetitively and accurately for various scenarios. The

calculated component values are automatically set in place in the companion TINA schematic

and you can check the result by simulation. This new feature is also very useful for

semiconductor and other electronics component manufacturers to provide application circuits

along with the design procedure.

Optimization: Using TINA's built-in Optimization tool unknown circuit parameters can be

determined automatically so that the network can produce a predefined target output values,

minimum or maximum. Optimization is useful not only in the design of electronic circuits, but

also in teaching, to construct examples and problems. It is a very good tool to refine the results

provided by a design procedure or tune already working circuits.

Integrated PCB design: The new fully integrated layout module of TINA has all the features you

need for advanced PCB design, including multilayer PCB's with split power plane layers,

powerful autoplacement & autorouting, rip-up and reroute, manual and "follow-me" trace

placement, DRC, forward and back annotation, pin and gate swapping, keep-in and keep-out


areas, copper pour, thermal relief, fanout, 3D view of your PCB design from any angle, Gerber

file output and much more.

Advanced presentation tools: Make stand-out reports and presentations of schematic

diagrams, annotations, formulas provided by symbolic analysis, Bode plots, Nyquist diagrams,

poles and zeros, transient responses, digital waveforms, and other data using linear or

logarithmic scales. Customize presentations using TINA's advanced drawing tools to control

text, fonts, axes, line width, color and layout. You can create, edit and print documents directly

inside TINA or cut & paste your results into your favorite word processing or DTP package.

Importing Spice models: Create new TINA components from any Spice subcircuit, whether

created by yourself, downloaded from the Internet, obtained from a manufacturer's CD or from

portions of schematics turned into subcircuits. TINA automatically represents these subcircuits

as a rectangular block, but you can create any shape you like with TINA's Schematic Symbol

Editor. You can also use TINA's parameter extractor program to calculate model parameters

from catalog or measurement data and then add the new devices into the catalog.

Educational tools: Educational tools. TINA also includes unique tools for testing students'

knowledge, monitoring progress and introducing troubleshooting techniques. With optional

hardware it can be used to test real circuits for comparison with the results obtained from

simulation. With the Live 3D breadboard tool you can automatically build a life-like 3D picture

of a solderless breadboard. When you run TINA in interactive mode, components like switches,

LEDs, instruments, etc. become "live" and will work on the virtual breadboard just as in reality.

You can use this capability of TINA to prepare and document lab experiments. You can also use

the integrated Flowchart Editor and Debugger to generate and debug the MCU code, learning

and teaching microcontroller programming.

Virtual Instruments: Oscilloscope, Function Generator, Multimeter, Signal Analyzer/Bode

Plotter, Network Analyzer, Spectrum Analyzer, Logic Analyzer, Digital Signal Generator, XY

Recorder.


Real time measurements: TINA is far more than a circuit simulator with virtual measurements.

You can install optional, supplementary hardware that allows real-time measurements

controlled by TINA's on screen virtual instruments.

TINALab II multifunction PC Instrument: With the TINALab II high speed PC instrument you can

turn your laptop or desktop computer into a powerful, multifunction test and measurement

instrument. Whichever instrument you need multimeter, oscilloscope, spectrum analyzer, logic

analyzer, arbitrary waveform generator, or digital signal generator it is at your fingertips with a

click of the mouse. In addition TINALab II can be used with the TINA circuit simulator program

for comparison of circuit simulation and measurement results as a unique tool for circuit

development, troubleshooting, and the study of analog and digital electronics.

Tina Workspace:


2. Wien Bridge Oscillator

A Wien bridge oscillator is a type of electronic oscillator that generates sine waves. It can

generate a large range of frequencies. The oscillator is based on a bridge circuit originally

developed by Max Wien in 1891.

2.1 Theory:

The oscillator can also be viewed as a positive gain amplifier combined with a band pass

filter that provides positive feedback.

It uses a feedback circuit consisting of a series RC circuit connected with a parallel RC of the

same component values producing a phase delay or phase advance circuit depending upon the

frequency. At the resonant frequency the phase shift is “0” degrees. Consider the circuit below:

The network consists of a series RC circuit connected to a parallel RC forming basically a High

Pass Filter connected to a Low Pass Filter producing a very selective second-order frequency

dependant Band Pass Filter with a high Q factor at the selected frequency.

At low frequencies the reactance of the series capacitor (C1) is very high so acts like an open

circuit and blocks any input signal at Vin. So there is no output signal V out. At high frequencies,


the reactance of the parallel capacitor, (C2) is very low so this parallel connected capacitor acts

like a short circuit and no output again.

However between these two extremes the output voltage reaches a maximum value with the

frequency at which this happens being called the “Resonant Frequency”. At this resonant

frequency, the circuits reactance equals its resistance as Xc = R so the phase shift between the

input and output equals zero degrees.

2.2 Circuit Diagram:

2.3 Design:

R1=R2=R


After substituting ‘s’ with jw,and equating imaginary part to zero because H(s) must be real. We

get

2.4 Procedure:-

Connect the circuit is as shown in the circuit diagram. Keep the resistance and capacitor values

R1 = R2 = R and C1 = C2 = C and switch on the power. Adjust the voltage sensitivity band switch

and time – base band switch such that at least two or more complete sine waves are observed

on the screen of CRO. Also adjust the resistance R3 value till the wave formed on the CRO

screen is stationary.

Note R and C values in the table and measure the peak to peak horizontal length (l) of one sine

wave. Multiply this value with the corresponding time-base (t) value. This product gives the

time period (T) of the generated sine wave. The reciprocal of time period gives the

experimental frequency of the sine wave. On substitution of Rand C values in the above

equation, it gives theoretical frequency. The theoretical and experimental frequencies are

equal. The experiment is repeated by changing the value of R or C.


2.5 Applications:

Wein’s Bridge Oscillator as simplified frequency controller:-

High-quality audio signal generators make extensive use of the Wien-Bridge oscillator as a basic

building block. The number of frequency decades covered by these instruments is variable,

three being the minimum, and they all cover at least the audible spectrum ranging from 20 Hz

to 20 kHz. In addition, frequency can be continuously varied over each decade.

Amplitude Stabilization:

The key to the Wien bridge oscillator's low distortion oscillation is an amplitude stabilization

method that does not use clipping. The idea of using a lamp in a bridge configuration for

amplitude stabilization was published by Meacham in 1938. The amplitude of electronic

oscillators tends to increase until clipping or other gain limitation is reached. This leads to high

harmonic distortion, which is often undesirable.

Hewlett used an incandescent bulb as a power detector, low pass filter and gain control

element in the oscillator feedback path to control the output amplitude. The resistance of the

light bulb filament increases as its temperature increases. The temperature of the filament

depends on the power dissipated in the filament and some other factors. If the oscillator's

period (an inverse of its frequency) is significantly shorter than the thermal time constant of the

filament, then the temperature of the filament will be substantially constant over a cycle. The

filament resistance will then determine the amplitude of the output signal. If the amplitude

increases, the filament heats up and its resistance increases. The circuit is designed so that a

larger filament resistance reduces loop gain, which in turn will reduce the output amplitude.

The result is a negative feedback system that stabilizes the output amplitude to a constant

value. With this form of amplitude control, the oscillator operates as a near ideal linear system

and provides a very low distortion output signal. Oscillators that use limiting for amplitude

control often have significant harmonic distortion. At low frequencies, as the time period of the

Wien bridge oscillator approaches the thermal time constant of the incandescent bulb, the

circuit operation becomes more nonlinear, and the output distortion rises significantly.


http://en.wikipedia.org/wiki/Negative_feedback

http://en.wikipedia.org/wiki/Incandescent_bulb

http://en.wikipedia.org/wiki/Gain

2.6 Advantages

1. Provides a stable low distortion sinusoidal output over a wide range of frequency.

2. The frequency range can be selected simply by using decade resistance boxes.

3. The frequency of oscillation can be easily varied by varying capacitances C1 and

C2 simultaneously. The overall gain is high because of two transistors.

2.7 Disadvantages

1. The circuit needs two transistors and a large number of other components.

2. The maximum frequency output is limited because of amplitude and the phase-shift

characteristics of amplifier.

2.8 Output of Wein’s Bridge Oscillator:

Result: Wein’s Bridge oscillator is designed and implemented successfully.


3. Inverting Adder using IC741

3.1 Theory:

Inverting adder is similar to inverting amplifier except that it has more than one input. Different

input signals are connected to inverting terminal (–) through number of input resistors and non-

inverting terminal (+) is grounded.

The output is 180 “OUT OF PHASE” with respect to input. Hence, the feedback is negative.

3.2 Circuit Diagram:

3.3 Design:

Suppose V1, V2 and V3 are input signals and Vo is output signal, as shown in circuit

diagram. Let V1, V2, V3 are three input signals at R1, R2 and R3 respectively. Due to the inputs,

three currents I1, I2 and I3 are produced. The currents can be calculated as follows: –

I 1=V 1

R1

. .. .. . .. .(1) I 2=V 2

R2

. .. .. . .. .(2) I 3=V 3

R3

.. .. .. . ..(3 ) because VA = 0

And If is feedback current flowing from point ‘A’ to output terminal of op amp.


It is given by:–

I f=−V oR f

. . .. .. . ..( 4 )

These currents mix at point A, to produce feedback current. Hence,

I 1+ I 2+ I 3=I f . . .. .. . ..(5 )

Putting the values of currents of equations (1), (2), (3) and (4) in equation (5) we get: –

(V 1

R1

+V 2

R2

+V 3

R3)=−V o

Rf. .. .. . .. .(6 )

Let R1 = R2 = R3 = Rf, then equation (6) becomes:

Vo = – (V1 + V2 + V3).

This is the required equation for output voltage of op amp.

3.4 Procedure:

Connect the circuit as shown in circuit diagram. Give three different voltages to non- inverting

terminal of op amp in which all the resistors are of same value. Calculate value of current in

each terminal connected to non inverting terminal of op amp and combine them by using KCL.

Calculate output voltage of circuit.

3.5 Applications:

Audio Mixer:

A popular application of the parallel summing circuit is audio mixing of analog signals from a

few voltage sources.


3.6 Output of Inverting Adder:

Result: Inverting adder is designed and implemented successfully.


4.Reference:

1. http://www.tina.com

2. http:// www. wikipedia .org

3. http://www.electronics-tutorials.html

4. http:// www.calvin.edu

5. http://www.ecircuitcenter.com

6. http://www.circuitstoday.com


http://www.ecircuitcenter.com/

http://www.calvin.edu/

http://www.electronics-tutorials.html/

http://www.wikipedia.org/

http://www.tina.com/

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