EE 368 Electronics Lab. Experiment 10 Operational Amplifier Applications (2)

Transcription

1 EE 368 Electronics Lab Experiment 10 Operational Amplifier Applications (2)

2 1 Experiment 10 Operational Amplifier Applications (2) Objectives 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. Theory 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). LM 324 Figure 1: Opamp IC chips pinout configurations

3 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: t 1 V o (t) = 1 RC V in(t)dt 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: V o (t) = 1 RC d dt V in(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 (V γ ). This offset voltage (V γ ) 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 0 T = 2RC ln ( 2R 2 R ) 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 (R 1 = R 2 and C 1 = C 2 ) producing a phase delay or phase advance circuit depending upon the frequency. The frequency of the output signal is given by: 1 f = 2πR 1 C 1

4 3 Procedure Equipment & Part List Oscilloscope. Function Generator (FG). Two Digital Multi-Meters (DMM). Resistors of values (3x10, 1, 2x15) kω. Capacitor values (1, 0.1 )µf. DC power supplies. Project Breadboard. Connection wires and coaxial cables Op-Amp 741 or LM324. 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 V p 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 V o (t) Signal on the respective Oscilloscope screen in the sheet answer. 5) Comment on the output signal and its relation to the input signal. C R V O V in Figure 2: The Inverting Integrator circuit.

5 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 2V p 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 V o (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. 4 R C V O V in Figure 3: The Inverting Differentiator circuit.

6 5 Part C: The Half wave Precision Rectifier circuit 1) Construct the circuit shown in Figure 4 using R L = 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 400mV p 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. V in V O R L 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?

7 6 Part D: The Square Wave generator circuit 1) Construct the circuit shown in Figure 5 by using R = 10KΩ, R 1 = R 2 = 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? R C V O R 1 R 2 Figure 5: The Square Wave generator circuit.

8 7 Part E: The Sine Wave Oscillator circuit 1) Construct the circuit shown in Figure 6 by using C 1 = C 2 = 0. 1μF, R 1 = R 2 = 1kΩ, R 3 = 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. C 1 R 4 R 3 V O R 1 C 2 R 2 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?

9 The University Of Jordan School of Engineering Electronics Lab Report Experiment No.: Student Group: Experiment Name: Students Name: 1) 2) 3) 4)

10 Report of Experiment 10 Operational Amplifier Applications (2) Part A: The Inverting Integrator circuit 5- Comment on the output signal and its relation to the input signal Part B: The Inverting Differentiator circuit Sine wave input signal Triangle wave input signal

11 Square wave input signal 5- Comment on the output signal and its relation to the input signal.. 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? 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?

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