A

Project Report

On

Simple Function Generator At

Electronics & Communication Engineering Department

Institute of Technology

Nirma University of Science & Technology

: Prepared By :

Pravin Gareta (08BEC156)

Aniket Prajapati (08BEC151)

Jaydeep Malhotra (08BEC158)

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:Acknowledgement:

There is much difference between saying and doing. So, to get theoretical knowledge is not enough. It provides only base. In our fifth semester Modern Measurement and Instrumentation will be there. In this lab we have to in touch with our practical instruments like Ammeter, Voltmeter, Different type of bridges , CRO , Thermister , LVDP. And we also study about the various component of the Measurement and At last we have to submit one project which will deal with the our Practical field. So, we make a one project namely ”Simple Function generator ” We put our lots of effort to do this project and try our best.

We believe that “Practical leads a man towards Performance”

In this project we thanks to our colleges which helps to motivate us.

At last we thankful to the Prof. P.C.Pandya Sir who help us to decide this project and encourage us.

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AIM : To make a Simple Function Generator

Apparatus : IC 741

Resistor : 100k,10k,27k,

Capacitor: 0.1uf,0.01uf,0.001uf

Circuit diagram:

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Working :

This is a simple function generator circuit that can produce the following waveforms: square wave, triangular wave, and sine wave.

The circuit's main components are four 741 IC's. The 741 is a op-amp IC. The first op amp in Figure is configured as an astable multivibrator, which continuously generates a square wave. Assume that C3 has no charge initially. The voltage at the inverting input is zero, while the voltage at the non-inverting input is very slightly positive (a ratio of the op amp's output offset voltage as determined by R3 and R2). This minute voltage difference at the inputs is enough to cause the op amp's output to swing to 'high'.

When the output becomes high, C3 starts charging up. The voltage at the inverting input soon exceeds that at the non-inverting input, forcing the output to swing to 'low', which discharges C3 again. At a certain point, the voltage at the non-inverting input exceeds that at the inverting input again, and the output of the op amp goes high again.

This cycle wherein the first op amp's output swings between 'low' and 'high' goes on indefinitely, generating the square wave.The two middle op-amps are both configured as integrators. The input to the second op amp is the square wave output of the first op amp. Being configured as an integrator, this op amp outputs a triangular wave (the integral of a square wave), as shown in Figure.

The triangular wave output of the second op amp is then fed into the third op amp, which is also configured as an integrator. The output of the third op amp is a sine wave (the integral of a triangular wave).

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The sine wave output of the third op amp is fed into the fourth op amp, which is configured as an inverting amplifier. The output of this last op amp is also a sine wave but opposite in phase as its input.

Advantage : Circuit should be simple It also cheap

Disadvantage: We can’t properly recognize difference between sine and

triangular on simple CRO.

Conclusion:

For our MMI subject we made a simple function generator circuit which produce square, triangular and sine wave. This circuit will be run and worked properly. For all the waveform we recognize, but minor difference between sine and triangular wave which we can’t recognize properly in simple CRO but in digital CRO it will be clearly seen.

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