EE 368

Electronics Lab

Experiment 10

Operational Amplifier Applications (2)

The Operational Amplifier (shown in Figure 1) has different applications, some of them is studied

in the last experiment, here we will test other applications such as the inverting integration, the

inverting differentiation, the precision half wave rectifier, square wave generator and sine wave

oscillator (Wien bridge oscillator).

Figure 1: Opamp IC chips pinout configurations

LM 324

To gain experience with Operational Amplifier (Op-Amp).

To study the Operational Amplifier applications as inverting integrator, inverting

differentiator, precision half wave rectifier, square wave oscillator and sine wave

oscillator.

Objectives

Theory

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Experiment 10

Operational Amplifier Applications (2)

The Inverting Integrator circuit, shown in Figure 2, is used to perform the mathematical

operation of inverting and integrating the input signal over time. The output voltage is given by:

𝑉𝑜(𝑡) = −1

𝑅𝐶∫ 𝑉𝑖𝑛(𝑡)𝑑𝑡

𝑡1

𝑡0

The Inverting Differentiator circuit, shown in Figure 3, is used to perform the mathematical operation

of differentiation for the input signal. The output voltage is given by:

𝑉𝑜(𝑡) = −1

𝑅𝐶∙

𝑑

𝑑𝑡𝑉𝑖𝑛(𝑡)

For the Half wave rectifier studied in Experiment 2, we saw that the output voltage has an offset about

0.7 volt due to the cut-in voltage (𝑉𝛾). This offset voltage (𝑉𝛾) is unacceptable in many practical

applications, so the Precision half wave rectifier circuit, shown in Figure 4, is used to form an ideal

diode where the offset voltage can be eliminated from the output signal. The other advantage from this

circuit is the possibility to rectify very small input signal without caring that the input voltage must

exceed the cut-in voltage of the diode.

The Square wave generator circuit, shown in Figure 5, is used to generate a square wave. It's the

reference voltage for the comparator depends on the output voltage. The period of the output signal (𝑇)

is given by the following equation:

𝑇 = 2𝑅𝐶 ∙ ln (2𝑅2

𝑅1+ 1 )

The Sine wave oscillator circuit (Wien Bridge Oscillator), shown in Figure 6, is used to produce a

sinusoidal output waveform. It uses a feedback circuit consisting of a series RC circuit connected with

a parallel RC of the same component values (𝑅1 = 𝑅2 and 𝐶1 = 𝐶2) producing a phase delay or phase

advance circuit depending upon the frequency. The frequency of the output signal is given by:

𝑓 =1

2𝜋𝑅1𝐶1

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Part A: The Inverting Integrator circuit

1) Construct the circuit shown in Figure 2 by using 𝑹 = 𝟏𝑲𝜴 and 𝑪 = 𝟏𝝁𝑭.

2) Switch On the function generator:

a) Set the shape to square-wave.

b) Set the frequency to 𝟐𝟎𝟎𝑯𝒛. c) Set the amplitude to 𝟏 𝑽𝒑−𝒑.

3) Switch ON the oscilloscope:

a) Connect CH1 to the input signal.

b) Connect CH2 to the output signal.

c) Set the Channel coupling for CH1 to DC and CH2 to AC.

4) Sketch the output signal 𝑉𝑜(𝑡) Signal on the respective Oscilloscope screen in the sheet answer.

5) Comment on the output signal and its relation to the input signal.

Figure 2: The Inverting Integrator circuit.

𝐶

𝑅

𝑉𝑂

𝑉𝑖𝑛

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Procedure

Oscilloscope. DC power supplies.

Function Generator (FG). Project Breadboard.

Two Digital Multi-Meters (DMM). Connection wires and coaxial cables

Resistors of values (3x10, 1, 2x15) kΩ. Op-Amp 741 or LM324.

Capacitor values (1, 0.1 )µF.

Equipment & Part List

Part B: The Inverting Differentiator circuit

1) Construct the circuit shown in Figure 3 by using 𝑹 = 𝟒𝟕𝟎𝜴 and 𝑪 = 𝟏𝝁𝑭.

2) Switch On the function generator:

a) Set the shape to sine wave.

b) Set the frequency to 𝟏𝟎𝟎𝑯𝒛.

c) Set the amplitude to 𝟐𝑽𝒑−𝒑

3) Switch ON the oscilloscope:

a) Connect CH1 to the input signal

b) Connect CH2 to the output signal

c) Set the coupling for both channels to AC coupling.

4) Sketch the output signal 𝑉𝑜(𝑡) signal on the respective Oscilloscope screen in the sheet answer.

5) Change the input signal shape to triangle wave and repeat step 4.

6) Change the input signal shape to square wave and repeat step 4.

7) Comment on the output signal and its relation to the input signal.

Figure 3: The Inverting Differentiator circuit.

𝐶

𝑅

𝑉𝑂

𝑉𝑖𝑛

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Part C: The Half wave Precision Rectifier circuit

1) Construct the circuit shown in Figure 4 using 𝑹𝑳 = 𝟏𝒌𝜴.

2) Switch On the function generator:

a) Set the shape to sine wave.

b) Set the frequency to 𝟏𝟎𝟎𝑯𝒛.

c) Set the amplitude to 𝟒𝟎𝟎𝒎𝑽𝒑−𝒑.

3) Switch ON the oscilloscope:

a) Connect CH1 to the input signal.

b) Connect CH2 to the output signal.

c) Set the coupling for CH1 to AC coupling and CH2 DC coupling.

Figure 4: The Half wave Precision Rectifier circuit.

4) Draw the output signal on the respective oscilloscope screen in the sheet answer.

5) Measure the output peak voltage from the oscilloscope screen.

6) What is the main difference between the rectified signals if we use Op-amp instead of using diode

only as in Experiment 2?

7) What is the effect on the output signal if the amplitude stay fixed but the frequency of the source is

increased to 𝟏𝒌𝑯𝒛? Explain why?

𝑅𝐿

𝑉𝑂

𝑉𝑖𝑛

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Part D: The Square Wave generator circuit

1) Construct the circuit shown in Figure 5 by using 𝑹 = 𝟏𝟎𝑲𝜴, 𝑹𝟏 = 𝑹𝟐 = 𝟏𝟓𝑲𝜴 and 𝑪 = 𝟎. 𝟏𝝁𝑭.

2) Switch ON the oscilloscope:

a) Connect CH1 to the output signal.

b) Set the coupling for CH1 to AC coupling.

c) Draw the output signal on the respective Oscilloscope screen in the sheet answer.

3) Measure the output signal frequency from the oscilloscope screen.

4) Calculate the output signal frequency using the formula in the theory and compare it with the

measured value from step 3.

5) Explain how can we change the output signal frequency?

Figure 5: The Square Wave generator circuit.

𝑅2

𝑉𝑂

𝑅

𝐶

𝑅1

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Part E: The Sine Wave Oscillator circuit

1) Construct the circuit shown in Figure 6 by using 𝑪𝟏 = 𝑪𝟐 = 𝟎. 𝟏𝝁𝑭, 𝑹𝟏 = 𝑹𝟐 = 𝟏𝒌Ω, 𝑹𝟑 = 𝟐𝟐𝒌Ω

and 𝑹𝟒 = 𝟏𝟎 𝒌Ω.

2) Switch ON the oscilloscope:

a) Connect CH1 to the output signal.

b) Set the coupling for CH1 to AC coupling.

c) Draw the output signal on the respective Oscilloscope screen in the sheet answer.

Figure 6: The Sine Wave Oscillator circuit.

3) Measure the output signal frequency from the oscilloscope screen.

4) Calculate the output signal frequency using the formula in the theory and compare it with the

measured value from step 3.

5) Explain how can we change the output signal frequency?

𝑅2

𝑉𝑂

𝑅3 𝐶1

𝑅1

𝐶2

𝑅4

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The University Of Jordan

School of Engineering

Electrical Engineering Department

Experiment No.: ______ Student Group: ______

Experiment Name: _______________________________________

Students Name:

1) __________________________________________

2) __________________________________________

3) __________________________________________

4) __________________________________________

Electronics Lab Report

0903368

Part A: The Inverting Integrator circuit

5- Comment on the output signal and its relation to the input signal.

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Part B: The Inverting Differentiator circuit

Sine wave input signal Triangle wave input signal

Report of Experiment 10

Operational Amplifier Applications (2)

Square wave input signal

5- Comment on the output signal and its relation to the input signal.

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Part C: The Half wave Precision Rectifier circuit

5- What is the main difference between the rectified signals if we use Op-amp instead of using diode

only as in Exp2?

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7- What is the effect on the output signal if the amplitude stay fixed but the frequency of the source is

increased to 𝟏𝒌𝑯𝒛? Explain why?

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Part D: The Square Wave generator circuit

3- Measure the frequency of the output signal from the scope screen and compare it with the calculated

frequency.

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4- Explain how can we change the frequency of the output signal?

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Part E: The Sine Wave Oscillator circuit

3- Measure the frequency of the output signal from the scope screen and compare it with the calculated

frequency.

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4- Explain how can we change the frequency of the output signal?

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