INC 253 Digital and electronics laboratory I Laboratory 4 Wave Shaping Diode Circuits Author: ID CoAuthors: 1. ID 2. ID 3. ID Experiment Date: Report received Date: Comments For Instructor Full Marks Pre lab 10 Results 15 Discussion 25 Questions 10 Conclusion 5 Total 65 Department of Control System and Instrumentation Engineering Faculty of Engineering King Mongkut s University of Technology Thonburi
Objectives To understand diode clipping circuits (clipper or limiter) To understand diode clamping circuits (clamper) Equipments Required Variable DC power supply x2 Function generator x1 Oscilloscope x1 Training Board Devices Required Resistors 5% tolerance: 680Ω, 10kΩ x1 per each item Capacitor 0.02µF, 0.1µF x1 per each item Silicon diode x2 PreLab 1. Clipping circuit I 680Ω V i D V o V B Figure 1. Calculate and plot the output signal (V O ) as shown in figure 1 compared with the input signal in the same graph. The sinusoidal input (V i ) has an amplitude of 10V PP and frequency of 1KHz. The DC bias voltage (V B ) is set to 3 volts. 2
2. Clipping circuit II D V i 680Ω V o V B Figure 2. Calculate and plot the output signal (V O ) as shown in figure 2 compared with the input signal in the same graph. The sinusoidal input (V i ) has an amplitude of 10V PP and frequency of 1KHz. The DC bias voltage (V B ) is set to 3 volts. 3. Clipping circuit III 680Ω V i D D V o V B1 V B2 Figure 3. Calculate and plot the output signal (VO) as shown in figure 3 compared with the input signal in the same graph. The sinusoidal input (Vi) has an amplitude of 10VPP and frequency of 1KHz. The DC bias voltage VB1 and VB2 are set to 3 volts and 1 volt, respectively. 3
4. Clamping circuit V i 0. 0 2 µ F D 6 8 0 Ω V o V B Figure 4. Calculate and plot the output signal (V O ) as shown in figure 4 compared with the input signal in the same graph. The sinusoidal input (V i ) has an amplitude of 10V PP and frequency of 1KHz. The DC bias voltage V B is set to 0 volts. Measure and plot the output signal compared with the input signal in the same graph. Procedure *** Note the following information before starting the lab: a) Set the vertical input coupling of your oscilloscope to DC coupling. b) Set both of ground position (CH1 and CH2) are the same position. c) For more information about clipping and clamping circuits, please use reference books same as in INC 225. 4
1. Clipping circuit I 1.1. Construct the circuit as shown in figure 1, and set the input signal and the DC bias voltage as in Pre_Lab 1. Measure and plot the output signal compared with the input signal in the same graph. 1.2. Change DC bias voltage to 5 volts and 3volts. Measure and plot the output signal compared with the input signal in the same graph. For DC bias voltage = 5 volt For DC bias voltage =3 volt 1.3. Reverse the direction of diode in figure 1, and set the input signal and the DC bias voltage as in Pre_Lab 1. Measure and plot the output signal compared with the input signal in the same graph. 5
2. Clipping circuit II 2.1 Construct the circuit as shown in figure 2, and set the input signal and the DC bias voltage as in Pre_Lab 2. Measure and plot the output signal compared with the input signal in the same graph. 6
2.2 Change the DC bias voltage to 5 volts and to 3 volts. Measure and plot the output signal compared with the input signal in the same graph. For DC bias voltage = 5 volt For DC bias voltage =3 volt 2.3 Reverse the direction of diode in figure 2, and set the input signal and the DC bias voltage as in Pre_Lab 2. Measure and plot the output signal compared with the input signal in the same graph. 7
3. Clipping circuit III 3.1 Construct the circuit as shown in figure 3, and set the input signal and the DC bias voltages as in Pre_Lab 3.Measure and plot the output signal compared with the input signal in the same graph. 3.2 Try to change an amplitude and shape of input (V i ), DC bias voltage V B1 and V B2. Investigate and explain the results. 8
4. Clamping circuit 4.1 Construct the circuit as shown in figure 4. The sinusoidal input (V i ) has an amplitude of 10V PP and frequency of 1KHz. The DC bias voltage V B is set to 0 volts. Measure and plot the output signal compared with the input signal in the same graph. 4.2 Set DC bias voltage V B to 2 volt and 2 volt. Measure and plot the output signal compared with the input signal in the same graph. For DC bias voltage = 2 volt For DC bias voltage =2 volt 4.3 Reverse the direction of diode in figure 4, and set the input signal and the DC bias voltages as in 4.1. Measure and plot the output signal compared with the input signal in the same graph. 9
4.4 Construct the circuit as shown in figure 4 again. Set the input signal to square wave which has an amplitude of 10V PP and frequency of 1KHz. The DC bias voltage V B is set to 0 volts. Measure and plot the output signal compared with the input signal in the same graph. 4.5 Change capacitor in figure 4 to 0.1 µf. Measure and plot the output signal compared with the input signal in the same graph. 10
4.6 Change capacitor in figure 4 to 0.1 µf and change resistor in figure 4 to 10 kω. Measure and plot the output signal compared with the input signal in the same graph. 4.7 Try to change an amplitude frequency and shape of input (V i ). Investigate and explain the results. 11