Laboratory Modules for Circuit Courses in St. Paul University Surigaocity
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ACKNOWLEDGMENT
The researchers would like to express their deepest gratitude to the following persons who extended their heartfelt support in making this thesis successful: First and for most, to Almighty God for giving them the wisdom and strength to complete and finish this particular study, for without Him, their design project would never reach its final form. Their beloved parents, brothers and sisters for their invaluable support that serves as our constant inspiration guiding them during difficult times of financial and moral crisis; Mrs. Karen Plaza, MSIT their research instructor for her remarkable assistance, patience and understanding in imparting her knowledge and expertise regarding research; Engr. Robert Bacarro, their research and technical adviser, for his inspiration and selfless sharing realistic ideas to acquire fulfillment of this scholastic task; Lastly, their friends for sharing their knowledge and ideas regarding theoretical aspect of the said design project.
Abucejo, Jervic B. Antinopo, James Arbil E. Digamon, Rosie Gay S.
ABSTRACT
This study aimed to design a low cost “Laboratory Modules for Circuit Courses in St. Paul University Surigao” to help engineering students developed their skills and knowledge regarding built-in laboratory experiments. This study is entitled Laboratory Modules for Circuit Courses in St. Paul University Surigao, was aimed to developed a better understanding of electronic circuit analysis and implement a simulation of actual laboratory experiment. Specially, it endeavored to attain the following objectives; to document the design project; to evaluate the performance of the system in terms of efficiency, accuracy, sensitivity and durability; to determine the acceptability level of the design project in terms of functionality and suitability, package design and cost of effectiveness. This study covered the documentation of the design including the input, process and output of the design. It also included the evaluation on the efficiency of the design which was confined to the experts in the field of electronics engineering and engineering students. The participants of the study were the experts of electronics engineering as well as engineering students. Purposive convenience sampling was utilized in determining the participants of the study. The data and information used in the development of study were taken from the textbooks for circuit analysis while its performance was taken from the evaluation forms and follow-up questions, with the aid of a statistical tool. The following were the major findings of the study. The modules for laboratory experiments was developed based on the theories presented in the textbooks for circuit analysis, this experiments was also anchored on the requirements of CHED Memorandum Order. As to the performance level of the system, the efficiency of the Laboratory Modules can really generate an output that fits to the corresponding experiments is rated very high by the participants. Despite that the accuracy of the output is depends on the input source but still it is rated very high by the experts. The design project is very high at 3.80 although, the sensitivity of the output is high, yet just like any other laboratory modules experiments it depends on the frequency that the users are going to input. As to acceptability level of the design project the functionality and suitability of the design in terms of capability of giving an accurate output data is found to be very high at 3.74 grand mean because it has a ability to train the engineering students and to developed their circuit analysis. Based on the foregoing findings, the conclusions are as follows: The Laboratory Modules for Circuit Courses in St. Paul University Surigao were possible and workable enough because it follows the CHED memorandum requirements in laboratory experiments for circuit courses. The overall performance of the Laboratory Modules for Circuit Courses is very high because it gives an realistic values that were based from the theories of each of the experiment and the laboratory modules were efficient enough in terms of capability of giving a reliable and accurate output data in conducting experiments for circuit courses and its ability to enhanced the skills of engineering students in circuit analysis. As to the outcome of the study, the researcher’s recommends, for the development of the test instruments, specifically the oscilloscope that used for measurement of time-varying signals and to portray the signal as a function of time, so that it can. It is highly recommended to make a laboratory manual as guide for the laboratory users for further understanding in the concepts of each of the experiment and lastly, modules should be detachable so that the students can see the PCB layout to verify the accuracy of the connections and to troubleshoot if problem occurs.
TABLE OF CONTENTS Page TITLE PAGE i ACKNOWLEDGMENT ii ABSTRACT iii CHAPTER 1 THE PROBLEM AND A REVIEW OF RELATED LITERATURE 1 Review of Related Literature 2 Synthesis of the Review 5 Conceptual Framework of the Study 6 Statement of Purpose and Objective 11 Assumptions 12 Significance of the Study 13 Scope and Limitation of the Study 14
2 METHOD 15
Research Design 15 Participants 15 Instruments 17 Procedures 17 Data Analysis 21
3 RESULTS AND CONCLUSIONS 23
4 FINDINGS, CONCLUSIOS, AND RECOMMENDATION 49
Findings 49 Conclusions 51 Recommendations 51
TABLES
1 Profile of the Experts 16 2 Performance of the Design 42 3 Profile of the System Users 16 4 Acceptability Level of the Design 45
FIGURES 1 IPO Diagram of the Study 8 2 Circuit Design 1 18 3 Circuit Design 2 18 4 Analysis of Resistive Networks Module 24 5 Resistance Bridge Circuit Module 26 6 Mesh and Nodal Analysis Module 27 7 Superposition and Linearity Theorem Module 28 8 Thevenin’s and Norton’s Theorem Module 29 9 Natural Responses of RC Circuit with DC Excitation Module 30 10 Natural Responses of RL Circuit with DC Excitation Module 31 11 Natural Responses of RLC Circuit with DC Excitation Module 31 12 Resistive, Inductive and Capacitive Circuits 33 with Sinusoidal Excitation Module 13 Impedance of a Series RLC Circuit Module 34 14 Impedance and Admittance of a Parallel RLC Circuit Module 36 15 Circuit Analysis for Network Theorems Module 37 16 Power in AC Circuits Module 38 17 Series Resonance Module 40 18 Parallel Resonance Module 41 19 Two Port Network Parameters Module 43 REFERENCES 53 APPENDICES
A. Letter to Validate Evaluation Form 56 B. Performance Evaluation Form 57 C. Acceptability Level Evaluation Form 59 D. CHED Memorandum Order of Laboratory Experiments 61 for Circuit Courses E. Schematic Diagram 65 F. Laboratory Experiment Guide 77
CURRICULUM VITAE 139
CHAPTER 1 THE PROBLEM AND A REVIEW OF RELATED LITERATURE
As the world embraced modernity, it also entered the world of electronics that leads to the stage of higher technology. Electronics has done many devices that made their lives more convenient, easier and simpler. These devices are developed in order to make them understand more complicated things and principles of the mysterious place they are living in. ‘Electronic devices nowadays are used not only as gadgets and household appliances but also as educational materials’ [1]. In electronics engineering, laboratory is one of the most important mediums of learning. It is important for the students to understand what they are studying and also, in order for them to learn in the way that is appropriate in this age. In able to become a productive engineer, the students must learn how to apply the theories to the real world, and so electronics has developed materials for an easier way of applying these theories. A laboratory module experiments encompasses many of the same engineering principles found in use today across a wide variety of industries. ‘It is just a higher form of hands-on laboratory experiment and are more efficient compare to the hands-on laboratory experiments because it has a built in circuit along with it, unlike that of the hands-on laboratory experiments’ [2]. The complexity of constructing a circuit especially with the newly engaged students in the subject will be lessened because of the built-in laboratory experiments in modules, so the students will be able to relate their studies to the experiment they are doing. Laboratory experiments must allocate enough resources in constructing the circuit. An equally important purpose of the laboratory modules is to further develop the student’s laboratory practice for experimentally testing and evaluating electrical circuits and systems. It is important that students develop this practice using modern laboratory equipment similar to that, which is used in industry. This laboratory module experiments maximizes the time of the students to study more the circuit and its output. Thus, it should enhance the theories presented in the classroom. Mostly in St. Paul University Surigao, the problems encountered by engineering students in every school are in terms of laboratory equipments, circuit constructing, errors in connections, and availability of components would be minimized if not solved. The result of this study is to establish laboratory modules for circuit courses that would somehow improve knowledge in circuit analysis as well as technical aspects among engineering students. It is within this context that the researchers thought of conducting a design project in making laboratory experiments in circuit subjects through laboratory modules.
Review of Related Literature This section presents the review of related literature of the study. The concept and study serve as support and bases to the development of this research. The basic premise of experimental learning theory is that the students learn as a result of doing or experiencing things in the world, and learning occurs when mental activity is suffused with physical activity[5]. Acquisition of manipulative skills is only possible through the use of real instruments and real experimental data. Therefore, to enhance learner learning’s, the institutions curriculum must integrate the effective characteristics of laboratory activities. The proposed laboratory modules are based on the CHED memorandum requirements for circuit courses such that; circuits 1 and circuits 2. Circuits 1 has eight experiments namely; Analysis of resistive networks, resistance bridge circuit, mesh and nodal analysis, superposition and linearity theorem, thevenin’s and norton’s theorems, natural responses of RC circuits with DC excitation, forced and natural responses of RL circuits with DC excitation, and forced and natural responses of RLC circuits with DC excitation. Moreover, Circuits 2 has eight experiments such that; resistive, inductive and capacitive circuits with a sinusoidal excitation; impedance of a series RLC circuit; impedance and admittance of a parallel RLC circuit; computer-aided software AC circuit analysis simulation for network theorems; power in AC circuits; series resonance; parallel resonance; and two-port network parameters. Technology has entered every single field of every single profession. Business, politics, and even education conquered already by this great phenomena. When it comes to engineering the field of computer and electronics are the leading competitors of this new era. In electronics, people who are diligently studying have a better future but in order for these people to achieve the pursued title they must have enough knowledge and having good laboratory practices is one of their basis. ‘According to the Northern Arizona University (USA), the exact nature of laboratory experiments for circuit courses differs from school to school. It also asserted that it depends on factors such as size of the school, laboratory facilities, and most importantly, on the laboratory equipments use in experiments. Laboratory experiments develop the student’s experimental skills, ability to work in teams and communicate effectively, learn from failure, and be responsible for their own results’ [3]. The University further affirmed that in any case, laboratory module experiments are a critical area of responsibility especially with the continuing rise in the education costs. Generally, the central role of learning built-in laboratory experiments is the impact on learning by the utilization of up-to-date laboratory equipments as well as the benefits and relevance of real-world applications in motivating students. Findings concerning the effectiveness of this hands-on approach to motivating students, enhancing their life-long learning skills and providing exposure to real world applications of electrical circuits in their field of study are presented. In addition, the importance and benefits of an instrumented resource centre that is available to all students throughout their undergraduate career is discussed. It is important that students develop this practice using modern lab equipment similar to that which is used in industry. ‘The major purpose of an educational laboratory trainer in the market is to provide students with a representation of a part of reality. The students are able to manipulate this representation, e.g. by changing the properties of the representation or by changing the conditions under which the representation operates’ [4]. The behavior of the representation as a result of these changes is similar to that of the represented part of the reality, but even with the advantages of laboratory trainers, laboratory modules are still important in the industrial technology curriculum. The professional success of a technologist is directly related to his/her ability to transfer knowledge gained in the academic environment to real-world situations. ‘The task of laboratory module experiments in engineering students is to ensure that the resources necessary to implement the experiments that would lead to the achievement of the goals of the University are available; and that these resources are used efficiently in the furthermore of educational ends’ [6]. One important aspect of laboratory module experiments is time management, having a constructed circuit where the test points are already place purposively and enough time in analyzing a circuit for a specified period of time in experiments.
Synthesis of the Review. The concepts obtained from the reading provided insights, which are related to the present study. All of the materials reviewed for purposes of this study gave useful insights and interferences on the value of built-in laboratory experiments. As a whole, the viewpoints of the researchers provided a solid foundation for this piece of endeavor. The concepts enabled the researchers to construct the research paradigm of the study. The authors in the cited literature and studies offered ideas fundamental to new laboratory equipment, from which the direction of this present study could be built upon. Van Schaick Zillesen gave significant ideas on experimental theory. Along with this, he emphasized the importance of hands-on laboratory schemes that would make the students, both knowledge and skill. Kaufman (2005) ‘focused on the task of laboratory modules and time management’. Van Schaick Zillesen (1990) ‘exposed the importance of reality in simulation and hands-on experiments’. The Northern Arizona University (USA) maintained that nature of lab experiments for circuit courses differs from school to school and this is dependent on factors such as size of the school, laboratory facilities, and most importantly, on the laboratory equipments use in experiments. University affirmed that in any case, a built-in laboratory experiment is a critical area of responsibility especially with the continuing rise in the education costs. The reviewed literature is similar to the present study because they dwell on laboratory equipment. They also consider the importance of properly hands-on laboratory in experiments; in this case, laboratory modules for circuit courses. On the other hand, the cited literature differs from the present investigation in terms of the techniques and ways of conducting an experiment, experiment were based from the CHED memorandum requirements.
Conceptual Framework of the Study In the light of the theories cited in the review literature and studies, this study aimed to develop a well-executed laboratory practice, where a laboratory modules experiment improves the engineering student’s skills and knowledge in electronic circuit analysis. Further studies also offered ideas fundamental to the new laboratory equipments, from which the direction of this present study could be built upon. In electronics engineering, laboratory is one of the most important mediums of learning. It is important for the students to understand what they are studying and also, in order for them to learn in the way that is appropriate in this age. This study is anchored on the theories in circuit courses, both DC and AC circuits. Traditionally, hands-on laboratory experiments consume too much time in constructing of the circuit than the analysis and data gathering of the experiments. The laboratory modules experiments is more likely the same as the hands-on laboratory experiments but the student’s time will be maximized on data gathering and circuit analysis because circuits where already built-in with corresponding test-points for data gathering. In terms of usage, it will be easy for the newly engaged users to utilize the laboratory modules because experiments are already built-in and easy to recognize its components. Findings concerning the effectiveness of this hands-on approach to motivating students, enhancing their life-long learning skills and providing exposure to real world applications of electrical circuits in their field of study are presented. In addition, the importance and benefits of an instrumented resource centre that is available to all students throughout their undergraduate career is discussed. It is important that students develop this practice using modern lab equipment similar to that which is used in industry.
INPUT PROCESS OUTPUT
Figure 1. Flow of the Study
Before the design comes into realization, there are things that have to be considered in making this project. One is combining all the collected information and facts related to the study. Figure 1 shows the input process output (IPO) diagram used for the creation of the design which is the laboratory modules for circuit courses. The diagram shows the materials to be used in making the circuit, the process in doing the project, how the materials are being connected, and how it will come up on its final output. The input block composed of is important materials to be used in this project. These include the CHED memorandum, multisim software, wires, pre-synthesized printed circuit board (PCB), electronic components such as; resistor, capacitor, soldering led to come up with the project being proposed and casing. The printed Circuit Board (PCB), the board that the electronics is mounted on usually made from copper coated insulator that has the circuit chemically etched onto one or both sides. Nowadays there are software’s used to make designs so it will be easier for the non-professional users to implant their designs on the PCB. The board is then drilled and the components are placed into the holes and then soldered the remaining copper. The resistor is an electronic device that has electrical resistance that is used for circuit protection, operation and current control. The capacitor is a device giving capacitance and usually consisting of conducting plates and foils separated by thin layers of dielectric (as air or mica); it stores energy voltage from the source. The process block shows how the materials are being processed to derive the output. This includes the data gathering, circuit designing, PCB making for the layout of the pre-synthesized PCB, circuit construction, circuits testing for any defects and errors and troubleshooting if ever errors occur, case design and lay-outing. In circuit designing the researchers were using software called ‘PCB Wizard (Student Version)’ for a faster way of designing a circuit with no error connections. After designing, the materials/components to be used were gathered like resistors and capacitors for circuit construction. In this stage, the components were tested if it has defects or if is not broken, usually it was constructed in the breadboard. While the circuit is being constructed, the design was printed into the PCB, in this stage the PCB were undergo in the process of etching after the printing. It was tested after constructing the circuit and troubleshoots if error occurs. When the circuit is done, the next stage was the designing of the case and its layout. It is important to design the case and layout because it was the exterior part of the design project. The user’s impression about the project depends on the case design and layout. The output block is the result of the input and process; it is the outcome of the input after it is being processed. This is the laboratory modules for circuit courses in St. Paul University Surigao which is a functional and effective product design for all the possible users. The overall description of the design was evaluated in terms of performance level and acceptability level. The performance level evaluation was based on efficiency, durability, accuracy and sensitivity and it was evaluated by the experts in the field of electronics. Efficiency pertains to the ratio of the useful energy delivered by a dynamic system to the energy supplied to it. Durability is the ability to exist for a long period of time without significant deterioration. The factors of the durability in the design were the wiring, soldering and placement of the materials. Accuracy is the preciseness, correctness and exactness of a certain device. Sensitivity is taken into account to find out the device to respond at immediate period of time. The device is needed to be test for the safety of the users. The acceptability level of the project was evaluated in terms of package design, cost effectiveness, functionality and suitability and evaluated by the engineering students whom taking-up circuit courses. The functionality and suitability refers to the project’s ability to work accordingly to its desired function. Package design if it is presentable for the user. Cost effectiveness if the design project is affordable for the user [7].
Statement of the Purpose and Objectives
This study aimed to produce a low cost Laboratory Modules for Circuit Courses in St. Paul University Surigao to help Engineering students develop their skills and knowledge regarding circuit analysis. The design project was aimed to achieve the following:
1. To document the technical specification of the laboratory modules in terms of input-process-output (IPO);
2. To determine the performance level of the experiment module as evaluated by experts in terms of:
1. efficiency;
2. accuracy;
3. sensitivity
4. durability
3. To determine the acceptability level of the experiment module as evaluated by users in terms of:
1. functionality and suitability;
2. package design;
3. cost effectiveness
Assumptions
In the process of designing the modules, the researchers assumed that: 1. The built-in laboratory experiments will operate by regulated power supply and a function
generator.
2. The experiments were based in the requirements of CHED Memorandum Order.
3. The circuitry of the design will have test points in order to gather data, a multi-tester for
circuit 1 and oscilloscope for circuit 2.
4. The electronic components will be available in the market.
5. The case will have a size of 14x11 inches.
Significance of the Study
The findings of this study are significant to the efficient practice of laboratory experiments in circuit courses. Specifically this will bring benefits to the following. School Administration. The success of this study will benefit St. Paul University Surigao because they have complied CHED memo requirements in circuit laboratory courses at lesser cost as compared to the expensive a built-in laboratory experiments available in the market. Instructors. The result of this study would also be beneficial to the instructor’s handling circuit courses because it lessen their time in supervising students doing their experiments. Thus, learning skills will be enhanced as taught in the classroom. Laboratory In-charge. This person would also benefit this study since it will also lessen his/her time in preparing the materials and equipments needed in the experiment. Storage space would also be minimized and kept in proper order. Engineering Students. This study would provide the engineering students less time in gathering data in the experiments and damage to electronic components. As a result, they would be more productive and knowledgeable in handling laboratory experiments and enhance their skills in circuit construction and analysis. Researchers. The design will give an idea for the researchers to improve and enhance further the present design project.
Scope and Limitation of the Study This study focused on the laboratory module experiments for circuit courses in St. Paul University Surigao. The design project is laboratory modules, powered by regulated power supply and a function generator, able to work in accordance with the CHED memo requirement. This project used test points for gathering data and it size is approximately 14x11 inches. The laboratory module experiments are limited only inside the laboratory room. The connectors used in measuring data are from laboratory equipment. The research project may limit on the numbers of experiments that could be conducted on the major process of the laboratory experiments for circuit subjects. In circuits 1, it has eight experiments and in circuits 2 also had eight experiments to be performed according to the CHED memo requirements. The study was conducted during the academic year 2012-2013 in St. Paul University Surigao. The participants of the study were chosen based on their courses and expertise. Courses indicates the students from different engineering programs whom already enrolled and passed circuit subjects and the expertise indicates the professionals from the fields of computer and electronics engineers who have a knowledge regarding circuit analysis.
CHAPTER 2
METHOD
This chapter discussed the methods and techniques used by the researchers in this study. It includes the research design, instruments, participants of the study, procedure, and data analysis tools.
Research Design
The study employed the applied-development research design approach because it is intended for the development of a new product by applying existing theories and concepts in circuit analysis. Applied experiment modules were based on CHED memo requirements for circuit courses. It also made used of descriptive-evaluative research design in order to determine the performance of the design evaluated by chosen participants.
Participants
In order for the researchers to obtain enough supportive information about the project and to come up with a nice design, the researchers obtained twenty five participants needed to evaluate the acceptability level and performance level of the project. There are five participants for the performance level evaluation who are the experts in the field of electronics. Twenty engineering students taking up circuit courses evaluated the acceptability level of the designed project in order for them to develop their analyzing skills and having more knowledge about laboratory module experiments. Furthermore, the experts was evaluated the performance level of the designed project because of their explicit knowledge in the field of electronics; hence purposive sample was used to determined the participants of this study.
In table 1, shows the profile of the experts in electronics and made their thorough evaluation on the performance level of the design project based on their observations to the said project. The percentage of the electronics engineers whom evaluated the design project is 60% and the remaining percentage are computer engineers.
In table 3, shows the profile and the numbers of the system users in laboratory modules and made their thorough evaluation on the acceptability level of the design project based on their observations to the said project.
Instruments The researchers used a modified evaluation form as the primary tool in gathering the data. With the instruments, the performance level of the design project was evaluated by the experts in terms of efficiency, accuracy, sensitivity, and durability. Another evaluation form was also used to evaluate the acceptability level of the design project by the users in terms of functionality and suitability, package design, and cost effectiveness.
Procedure Data gathering includes sampling technique to disseminate to the participants. The evaluation of the performance and acceptability level of the modules were processed by presenting an evaluation form to the participants of the study and letting them evaluated the designed project. The mean and standard deviation techniques were used after compiling the gather information to treat the results of the evaluation. The computed average mean helps the researchers to obtain the corresponding qualitative description of the design which shows the perception of the participants about the design. Thus, the quality of the designed project was acceptable to both the experts and the users alike. The designed project goes like this process.
Circuit Design 1
Figure 2. Circuit 1 Modules A regulated power supply is essential in the functioning of the research project and it is recommended to use the power supply with a variable output of 5v, 9v and 12v that is used in the laboratory modules. Multi-tester is an instrument that determines the output values of resistance, voltage and current. The circuit diagrams of a Laboratory Modules for Circuits 1 were tested first using an Electronic Workbench to lessen the effort spent on etching and soldering in an unchecked and malfunctioning circuit. Double checking the circuit was done with the use of a breadboard where in all the components was placed and connected with the used of wires. The used of a PCB greatly provided protection for the rest of the components and it also provided a fixed structure for permanently mounting the components. Circuit Design 2
Figure 2. Circuit 2 Modules
A function generator is essential in the functioning of the research project and oscilloscope is to determine the output of the waveform signal in a circuit. It is also highly recommended to use the function generator and oscilloscope for performing laboratory experiments with laboratory module. The circuit diagrams of a Laboratory Modules for Circuits 2 were also tested using an Electronic Workbench to lessen the effort spent on etching and soldering in an unchecked and malfunctioning circuit. Double checking the circuit was done with the use of a breadboard where in all the components was placed and connected with wires. The use of a PCB greatly provided protection for the rest of the components and it also provided a fixed structure for permanently mounting the components. The schematic diagram was constructed with the aid of PCB Express software. The diagram was printed in a photo paper with a specialized laser printer and its material was ironed with a PCB. The schematic diagram of the circuit was then transferred to the PCB ready to be mounted with components. After finishing the PCB, it was checked for unwanted open or short circuit paths. This is a common error in many PCB’s regardless of whether they are homemade or included in a kit. A multi-tester was used to verify connections. It is recommended to construct the PCB by Module so that circuit should be checked properly and to avoid complexity of the design. Start first with circuits 1 having eight experiments namely; Analysis of resistive networks, resistance bridge circuit, mesh and nodal analysis, superposition and linearity theorem, thevenin’s and norton’s theorems, natural responses of RC circuits with DC excitation, forced and natural responses of RL circuits with DC excitation, and forced and natural responses of RLC circuits with DC excitation follows in a step by step process. Then, a separate modules for Circuits 2 having also eight experiments such that; resistive, inductive and capacitive circuits with a sinusoidal excitation; impedance of a series RLC circuit; impedance and admittance of a parallel RLC circuit; computer-aided software AC circuit analysis simulation for network theorems; power in AC circuits; series resonance; parallel resonance; and two-port network parameters. After each construction, insert and solder the components. Begin with the resistors, capacitors, inductors and the terminals for output measuring. Before applying the power to the circuit, review your work to make sure that everything is in order. Watch out for cold solders and short circuits caused by solder bridges. Check the placement of wires in each test points. After applying the power supply and function generator in the circuit, do some testing and if there’s a problem do the troubleshooting. After it is proved that the Circuits 1 and Circuits 2 are running, make now the packaging for each circuits. Finally, interface the laboratory modules of Circuits 1 and 2 in their respective group. The circuit must always be checked before the power supply and function generator is applied to the circuit.
Data Analysis The researchers used of quantitative and qualitative data for the analysis and description of the design project. Thus, the following statistical and modeling tools were utilized for assessment. Mean. It refers to the mathematical average, which is the sum of values of variable and then dividing the total number of values involved [8]. It is used to get the average of the data gathered from the evaluation form for the participants. Standard Deviation. It measure of dispersion in a frequency distribution, equal to the square root of the mean of the squares of the deviations from the arithmetic mean of the distribution [9]. It also used after gathering all the data to treat the results of the evaluation. Schematic Diagram. An electrical print in which all the electrical components are represented with a schematic symbol. Schematic Diagrams shows the electrical relationship of all components, but not really the physical relationship of the components [11]. Schematic diagrams are used to understand the complete design project of the laboratory module for circuit courses. Block Diagram: A diagram in which the essential units of any system are drawn in the form labelled blocks or rectangles and their relation to each other is indicated by appropriate connecting arrows [12]. Block diagrams are used to understand complete design circuits by breaking them down into smaller block diagram shows how they are connected together. Flow Chart: A flowchart is a diagram made up of shapes and boxes, connected by arrows; each shape represents a step in the process and the arrows show the order in which they occur [13]. Flow chart gives guides to the flow of the design project in able to understand what is all about in that project. PCB Wizard Software: Is an open source software suite for electronic design automation for printed circuit boards (PCB) layout. It is used to for mechanically support and electrically connects electronic components using conductive pathways, tracks or signal traces [14]. It helps the researchers to design a project and having analysis in making a possible laboratory experiments based in CHED memo requirements.
CHAPTER 3
RESULTS AND DISCUSSIONS
This chapter presents the overview of the system, design specification, performance level of the design, the acceptability level of the designed project and cost of effectiveness.
Design Specification The laboratory module for circuit courses is a kind of laboratory equipment that gives fully educational and skill-enhancing training to the principles of circuit analysis. These laboratory modules were categorized in two major divisions, circuits 1 and circuits 2. At circuits 1 side, the user performed an experiment in DC circuit form where the input of the laboratory modules experiments is powered by a regulated variable power supply having an output voltage of 5V, 9V and 12V and multi-tester instrument to determined output values. These laboratory modules depend on the input source in giving an accurate data in performing laboratory experiments. In gathering a data, there are already test-points placed in every module for measuring the required values in each experiment and give enough information and ideas for the users in performing an experiment. Furthermore, in circuits 2 it is powered by the function generator and the oscilloscope determines the output in a form of signal. Same with circuits 1, it has test points placed in a circuit to determined values and the waveform signal in each experiment. Circuit 1 Modules
As stated by Hasan Demirel from the book of fundamentals of electric circuits for analysis of resistive networks, “that in series circuit the voltage drops add to equal total voltage, all components shared the same current and resistance add to equal total resistance. In parallel, all components shared the same voltage and branch currents add to equal total current and for series-parallel circuit, identify which part of the circuit are series or parallel, then selectivity applies series and parallel rules as necessary. After determining the unknown values, Ohm’s Law method must be used. Ohm’s Law states that the current flowing in a circuit is directly proportional to the voltage and inversely proportional to the resistance and this arrives at the usual mathematical equation that describes this relationship: I = V / R”. Series Circuit [pic]
Parallel Circuit
[pic]
Series-Parallel Circuit [pic] Figure 4. Analysis of Resistive Networks Module
Resistance Bridge Circuit, Module 2. This experiment shown in Figure 5, is to illustrate the role of series resistors in a form of voltage divider. When the current through the multi-tester becomes zero, the ratio of two known resistors is exactly equal to the ratio of adjusted value of variable resistance and the value of unknown resistance. In this way the value of unknown resistance can easily be measured by using a Wheatstone bridge. In this experiment, they need to consider the two aspects such that, “when no current flows through the ammeter, the Wheatstone bridge circuit is said to be balanced by varying resistor R until the multi-tester indicates zero reading and this condition, the voltages on both sides of the meter are identical. If there is a current flow through the ammeter, the Wheatstone bridge circuit is said to be unbalanced where the resistor is not varying and voltages are not identical to the multi-tester.”
A +
Figure 5. Resistance Bridge Circuit Module
Mesh and Nodal Analysis, Module 3. This experiment shown in Figure 6, “deals with the study of voltages across each resistor and the voltage at each node to illustrate the concept of nodal analysis and every junction in the network that represents a connection of three or more branches is regarded as a node. One node is always considered a reference node or zero-potential point, then current equations are written for the remaining junctions using Kirchhoff’s current law (KCL).And the current at each branch to illustrate the concept of mesh analysis where it involves a set of independent loop currents assigned to as many meshes as exist in the circuit, and these currents are employed in connection with appropriate resistances when the Kirchhoff voltage law (KVL) are written [16].
[pic]
[pic] Figure 6. Mesh and Nodal Analysis Module
The Superposition Theorem and Linearity, Module 4. This experiment shown in Figure 7, “explains that in superposition theorem for electrical circuits states that for a linear system the response (Voltage or Current) in any branch of a bilateral linear circuit having more than one independent source equals the algebraic sum of the responses caused by each independent source acting alone, while all other independent sources are replaced by their internal impedances. The superposition has a conditions such that, replacing all other independent voltage sources with a short circuit (thereby eliminating difference of potential. i.e. V=0, internal impedance of ideal voltage source is ZERO (short circuit) and Replacing all other independent current sources with an open circuit (thereby eliminating current. i.e. I=0, internal impedance of ideal current source is infinite (open circuit). And for linear system, this means that if they supply more input to the circuit, then they also get more output that is proportional to their input”[17]. [pic] Figure 7. Superposition and Linearity Theorem Module
Thevenin’s and Norton’s Theorems, Module 5. This experiment shown in Figure 8, “states that in Thevenin’s theorem any network with two terminals a and b can be replaced by a single voltage source (VTH) in series with a single resistance, (R) and Norton’s theorem states that the in any two open terminals a and b can be replaced by a single current source (Isc) in parallel with a single resistance, (R). Therefore, it determines the equivalent circuits by measuring the open circuit voltage and short circuit current of the given circuits. Using the principle of superposition along with Thevenin's and Norton's theorems to reduce complex circuits to simple voltage and current source models”. [pic] Figure 8. Thevenin’s and Norton’s Theorem Module
Natural Responses of RC Circuit with DC Excitation, Module 6. This experiment shown in Figure 9, deals with voltage, currents that change over time and the time dependent response of an RC circuit. At position 1 of the switch, the source is applied across the series RC and the capacitor will charge (charging phase). When the switch to position 2, the stored energy (1/2 CV2) and charge (Q) will be discharged through the same resistor (R) until it will become zero at some time. Switching from 1 and 2 positions will repeat the process of charging and discharging the capacitor.” [pic] Figure 9. Natural Responses of RC Circuit with DC Excitation Module
Natural Responses of RL Circuit with DC Excitation, Module 6. This experiment shown in Figure 10, it deals with voltages, currents that change over time and the time dependent response of RL circuit elements. When the switch is at position 1, the inductor can store energy according to the formula ½ Ll2 hence called the storage cycle. At position 2 of the switch the store energy is dissipated by the resistance (R) and (R1) so it will decay to zero at some time.”
[pic] Figure 10. Natural Responses of RL Circuit with DC Excitation Module
Natural Responses of RLC Circuit with DC Excitation, Module 6. This experiment shown in Figure 11, deals with voltages and currents that change over time for both capacitor and an inductor. The two have opposing responses to a voltage when applied at t = 0 and when t = ∞. One is open and the other is short. The conditions for series RLC states that if t = 0 then i = 0 and if t = 0 then L(di/dt) = E. And also to consider the cases such that; over damped when (R/2L)2 > 1/LC, critically damped when (R/2L)2 = 1/LC, and under damped when (R/2L)2 < 1/LC.
[pic] Figure 11. Natural Responses of RLC Circuit with DC Excitation Module
Circuit 2 Modules
In accordance with Floyd A. Sweet from the Introduction to Electric Circuits, 8th edition for resistive, capacitive and inductive circuit with sinusoidal excitation, “in purely resistive circuits, the current and voltage both change in the same way, and at the same time. This relationship is true, whether the applied voltage is direct or alternating. The main difference in AC circuits is that the voltage continues to change in a way that depends on the shape of the input wave. When a sine wave voltage is applied to a purely resistive circuit, it produces a sine wave (sinusoidal) current. Both waveforms attain their peak values at the same time, and pass through zero at the same time. Voltage and current in a purely resistive circuit are therefore said to be in phase with each other. Capacitance has the property of delaying changes in voltage. That is, the applied voltage reaches steady state only after a time dictated by the time constant. In AC circuit voltage and current are changing continuously, and in a purely capacitive AC circuit the peak value of the voltage waveform occurs a quarter of a cycle after the peak value of the current. Therefore a phase shift is occurring in the capacitor, the amount of phase shift between voltages and currents are +90° for a purely capacitive circuit, with the current leading the voltage. The opposite phase shift to an inductive circuit. In a purely inductive circuit the voltage and current waveforms are not in phase. This causes the current to reach its peak value some time after the voltage. So in an inductive circuit, current lags voltage” [26].
Resistive I + Oscilloscope Function Generator
Capacitive I + Oscilloscope Function Generator
Inductive
I + Oscilloscope Function Generator
Figure 12. Resistive, Inductive and Capacitive Circuits with Sinusoidal Excitation Module
According to Floyd A. Sweet from the Introduction to Electric Circuits, 8th edition for impedance of a series RLC circuit, “as the three vector voltages are out of phase with each other, XL, XC and R must also be "out-of-phase" with each other with the relationship between R, XL and XC being the vector sum of these three components thereby giving us the circuits overall impedance, Z. The impedance Z of a series RLC circuit depends upon the angular frequency, ω as do XL and XC If the capacitive reactance is greater than the inductive reactance, XC > XL then the overall circuit reactance is capacitive giving a leading phase angle” [27].
RL Circuit I + Oscilloscope Function Generator
RC Circuit I + Oscilloscope Function Generator
RLC Circuit I + Oscilloscope Function Generator
Figure 13. Impedance of a Series RLC Circuit
As stated by Keith E. Holbert from the article of electric circuits for impedance and admittance of a parallel RLC circuit, “it produces complex impedances for each parallel branch as each element becomes the reciprocal of impedance, ( 1/Z ) with the reciprocal of impedance being called Admittance. Admittance is the reciprocal of impedance, Z and is given the symbol Y. In AC circuits admittance is defined as the ease at which a circuit composed of resistances and reactance allows current to flow when a voltage is applied taking into account the phase difference between the voltage and the current. The admittance of a parallel circuit is the ratio of a phasor current to a phasor voltage with the angle of the admittance being the negative to that of impedance” [28].
RC Circuit I + Oscilloscope Function Generator
RL Circuit I + Oscilloscope Function Generator
RLC Circuit I + Oscilloscope Function Generator
Figure 14. Impedance and Admittance of a Parallel RLC Circuit
According to Floyd A. Sweet from the Introduction to Electric Circuits, 8th edition for AC circuit network theorems, “In Norton theorem, states that any collection of voltage sources, current sources, and resistors with two terminals is electrically equivalent to an ideal current source, I, in parallel with a single resistor, R. Those sources mentioned above can also either be dependent or independent sources. In Thevenin's theorem for linear electrical networks states that any combination of voltage sources, current sources, and resistors with two terminals is electrically equivalent to a single voltage source (V) in series with a single series resistor (R). Those sources mentioned above can be either independent or dependent. Between terminals A and B, they need to find out V. Since it's open circuit and there is no current going through R1.Treat R1 as wire. Circuit become simple three series resistor and a voltage source. Secondly, find the current. Thirdly, find the sum voltage across R3 and R2” [29].
As stated by Hasan Demirel from the book of fundamentals of electric circuits for power in AC circuit, “that for varying voltages and currents, the power delivered to a load is also varying. For AC sinusoidal voltages and currents, the real power in watts dissipated in an ac RL, RC or RLC circuit is dissipated in resistance only. There is no real power dissipation in a reactive element such as inductor or capacitor. In a reactive element, energy is stored during one-half the AC sinusoidal cycle and released during the other half of the AC sinusoidal cycle. The power in a reactive element is called reactive power (Q) and is measured in VARS and real power dissipated in an AC load can be calculated form P=I2R”. RL Circuit
I + Oscilloscope V Function Generator
RC Circuit
I + Oscilloscope V Function Generator
RLC Circuit
I + Oscilloscope V Function Generator
Figure 16. Power in AC Circuits Module
In accordance with Hasan Demirel from the book of fundamentals of electric circuits for series resonance, “that a resonant circuit, also called a tuned circuit consists of an inductor and a capacitor together with a voltage or current source. A network is in resonance when the voltage and current at the network input terminals are in phase and the input impedance of the network is purely resistive. How the steady state amplitude and the phase angle of the current vary with the frequency of the sinusoidal voltage source. As the frequency of the source changes, the maximum amplitude of the source voltage (Vm) is held constant. The frequency at which the reactance of the inductance and the capacitance cancel each other is the resonant frequency (or the unity power factor frequency) of this circuit” [31]. RLC Circuit
I A + Oscilloscope Function Generator B
RCL Circuit I A + Oscilloscope Function Generator B
Figure 17. Series Resonance Module
Consistent with Hasan Demirel from the book of fundamentals of electric circuits for parallel resonance, “A parallel resonant circuit consists of a resistor, a capacitor, and an inductor in parallel, typically driven by a current source. At some frequency the capacitive and inductive reactances will be of the same magnitude, and as they are 180 degrees in opposition, they effectively nullify each other. At any lower or higher frequency the inductive or capacitive reactance will shunt the resistance. The result is a maximum impedance magnitude at resonance, and thus, a maximum voltage. Any resistance value in series should be transformed into a parallel resistance in order to gauge its effect on the system voltage. The combined parallel resistance sets the Q of the circuit and can be defined as the ratio of the combined resistance to the resonant reactance, Q=R/X, which also corresponds to the ratio of the resonant frequency to the circuit bandwidth, Q=f0/BW” [32].
RLC Circuit
A + Oscilloscope Function Generator B C D I
RCL Circuit
A + Oscilloscope Function Generator B C D I Figure 18. Parallel Resonance Module
As stated by Floyd A. Sweet from the Introduction to Electric Circuits, 8th edition for two port network parameters, “A two-port network is simply a network with four terminals which are arranged into pairs called ports. The network is characterized by input voltage V1 and current I1 while the output is characterized by voltage V2 and current I2. In two terminals constitute a port if the currents applied to them satisfy the essential requirement known as the port condition: the electric current entering one terminal must equal the current emerging from the other. It is presumed that no energy sources lie within the two port network, which implies that any energy storage elements are embedded therein, zero state conditions apply. Energy is therefore applied to the two port system at only its input port” [33].
A B
I I + + C V2
D
Figure 19. Two Port Network Parameters
Performance Level of the Design The list tables below are the performance evaluation results of the design in terms of efficiency, accuracy, and durability. The results of the evaluation were tallied and its mean and standard deviation was derived. The qualitative description of the design is based on the following parameters:
|Variables | M | SD |Qualitative Description |
|Efficiency: | | | |
|Power consumption of the module. |3.60 |0.5477 |Very High |
|Time consumption in conducting an experiment. |4.00 |0.0000 |Very High |
|Users can work well with the module. |3.80 |0.4472 |Very High |
|Easy connection of test instruments in the module. |4.00 |0.0000 |Very High |
| Total Mean |3.85 |0.2236 |Very High |
|Accuracy: | | | |
|Measuring input data |4.00 |0.0000 |Very High |
|Measuring output data |3.20 |0.4472 |High |
|Measuring data in test points |3.80 |0.4472 |Very High |
|Power source measurements |3.65 |0.5477 |Very High |
| Total Mean |3.65 |0.2236 |Very High |
|Sensitivity: | | | |
|Working above & below the operating voltage |3.80 |0.4472 |Very High |
|Working above and below room temperature |4.00 |0.0000 |Very High |
|Working despite vibrations of the module |3.60 |0.5477 |Very High |
| Total Mean |3.80 |0.2991 |Very High |
|Durability: | | | |
|Components placement in PCB |3.80 |0.4472 |Very High |
|Design of the casing |4.00 |0.0000 |Very High |
|Good wiring practice |3.80 |0.4472 |Very High |
|Placement of the test points |3.60 |0.5477 |Very High |
|Total Mean |3.80 |0.2092 |Very High |
|Grand Mean |3.78 |0.1488 |Very High |
The total mean of the efficiency of the design is rated very high at 3.85 and its standard deviation was 0.2236 by the experts in circuit analysis because at different voltage source; AC and DC supply, the laboratory modules can really generate an output that fits to the corresponding experiments and less time consumption in performing laboratory experiments and also they were able to acquire the approximate values in terms of resistance, voltage, current and waveform signals by the use of input source instrument and the test points placed in the circuit purposively. The power consumption of the project got the lowest rate of 3.60 because there are times that the module had a power shortage due to the instruments that being used causes the fluctuation of the outputs. The accuracy of the design shows above that the mean in measuring output data got the lowest rate at 3.20 and 0.447 standard deviation because the experts find out that the output of the circuit on the module depends on the capability of the equipments to generate accurate output and the measuring input data got the highest rate at 4.0 because the users noticed that the modules were capable of giving approximate values regarding with the theoretical and experimental values. The total mean rated very high at 3.65 because the experts satisfied with the performance of the modules specifically in generating output values. The sensitivity of the design was assessed by the electronic experts. The design is very high at 3.80 and having a standard deviation of 0.2991 because the laboratory modules gave realistic output despite it relies on the input source. Although, the sensitivity of the output is very high, yet just like any other built-in laboratory experiments it depends on what the users are going to supply to the modules. Working despite vibrations of the modules got the lowest rate at mean of 3.60 and a standard deviation of 0.547 because there are times that the modules deflects its output due to fluctuations of the input source. The durability of the design was rated very high in terms of components placement in PCB because the experts noticed that the modules were presentable enough and well-organized. Also the design of the casing was rated very high because they were able to recognize its simplicity and being light among other laboratory modules. The placement of the test points got the lowest rate of 3.60 because this was not observed by the experts very keenly were it should be carefully observed so that it will not be difficult for the users during troubleshooting. And the grand mean for the performance level of the design project was rated very high at 3.78 because the experts were clearly satisfied with the performance of the laboratory modules.
Acceptability Level of the Design The following are the tables that summarize the acceptability level of the design in terms of functionality and sustainability, package design and cost effectiveness. The results were tallied, mean, standard deviation was calculated and qualitative description was labeled as to the same parameters presented in the performance level.
Table 4: Acceptability Level of the Design
|Variables |Mean |SD |Qualitative Description |
|Functionality and suitability: | | | |
|Connectivity of the design to external device |3.80 |0.4140 |Very High |
|Ease of gathering data from the design |3.85 |0.3663 |Very High |
|Availability of terminals |3.70 |0.4702 |Very High |
| Total Mean |3.78 |0.3302 |Very High |
|Package Design: | | | |
|Durability of the case |3.70 |0.4702 |Very High |
|Size of the case |3.70 |0.4703 |Very High |
|Color of the case |3.75 |0.4443 |Very High |
|Weight of the case |3.55 |0.5104 |Very High |
| Total Mean |3.68 |0.2821 |Very High |
|Cost of Effectiveness: | | | |
|Cost of the casing |3.85 |0.3663 |Very High |
|Cost of materials |3.75 |0.4423 |Very High |
|Cost of labor |3.80 |0.4103 |Very High |
|Overhead cost |3.70 |0.4702 |Very High |
| Total Mean |3.78 |0.3234 |Very High |
| Grand Mean |3.74 |0.2444 |Very High |
The functionality and suitability of the design was rated very high at total mean of3.78 and having a standard deviation of 0.3302 because the users find out that the modules can really give reliable and accurate output. The availability of the test points got the lowest rating at mean of are found to be very satisfactory but got the lowest rating since it is only limited, thus, not all of the electronic establishments here in Surigao are able to convey the said test points. But still, the modules were rated very high at 3.78 because the users clearly understand the given output by the modules based from the theories. The package design of the project in terms of weight of the casing got the lowest mean of 3.55 and having a standard deviation of 0.5104 because most of the participants compared the design project from the school’s laboratory module and the said module is lighter than the design project with regards to the materials used in the casing. Nevertheless, the durability was rated very high because the modules can withstand despite of vibrations. And the size and color of the casing were also rated very high because the users appreciate the simplicity and neatness of the modules from other laboratory modules. As to the cost of effectiveness of the design, the total computed cost of components was Php 7670.50 having evaluated with a rating of very high because it is much lesser compared to the other laboratory modules in the market. And the grand mean for the acceptability level of the design project was rated very high at 3.74 because the users were clearly satisfied and able to understand the concepts of the modules, specifically with the performance of the laboratory modules.
CHAPTER 4
FINDINGS, CONCLUSIONS, AND RECOMMENDATIONS
This chapter presents the findings, conclusion and recommendations of the study.
Findings Based on the data presented, the findings are summarized as follows. 1. The Laboratory Modules for Circuit Courses in St. Paul University Surigao was documented by following the CHED memorandum orders for laboratory experiments in circuit subjects. Here are the list of laboratory experiments for circuit 1 and 2. Circuit1: 1. Analysis of Resistive Networks 2. Resistance Bridge Circuit 3. Mesh and Nodal Analysis 4. Superposition and Linearity Theorem 5. Thevenin’s and Norton’s Theorem 6. Natural Responses of RC Circuit with DC Excitation 7. Natural Responses of RL Circuit with DC Excitation 8. Natural Responses of RLC Circuit with DC Excitation Circuit 2 1. Resistive, Capacitive and Inductive Circuit with Sinusoidal Excitation 2. Impedance of a Series RLC Circuit 3. Impedance and Admittance of a Parallel RLC Circuit 4. Circuit Analysis for Network Theorems 5. Power in AC Circuit 6. Series Resonance 7. Parallel Resonance 8. Two-port Network Parameters 2. Upon documented the design, the results on the performance level of the design project are the following: The laboratory modules are rated very high at 4.00 in its operation because it doesn’t show any inaccuracy in measuring values even if it varies with the input source. The laboratory modules also rated very high at 3.80 in generating output waveform signal at any frequency range. Although, the sensitivity of the modules, yet like any other built-in laboratory experiments, it still has signal distortion. The design project was rated high at 3 in terms of durability of the components placement in PCB, design of the casing and good placement of test points. 3. As to the acceptability level of the design project, the following are the results: The functionality and suitability of the laboratory modules in terms of capability of giving an accurate output data was found to be very high at 3.74 grand mean and its ability to train the engineering students. And the grand mean for the acceptability level of the design project was rated very high at 3.74 because the users was clearly satisfied and able to understand the concepts of the modules, specifically with the performance of the laboratory modules in terms of giving accurate output values.
Conclusions The following conclusions are drawn based on the findings: 1. The Laboratory Modules for Circuit Courses in St. Paul University Surigao was possible and workable enough to train engineering students because it follows the CHED memorandum requirements in laboratory experiments for circuit courses. 2. The overall performance of the Laboratory Modules for Circuit Courses was rated very high because it gives an realistic values that was based from the theories of each of the experiment. 3. The laboratory modules were efficient enough in terms of capability of giving an accurate and reliable output values in conducting laboratory experiments for circuit courses and its ability to enhanced the skills of engineering students in circuit analysis.
Recommendations The following recommendations are offered: 1. Development of the test instruments, specifically the oscilloscope that used for measuring of time-varying signals and portraying a signal as a function of time. 2. Modules should be detachable so that the students can see the PCB layout to verify the accuracy of the connections and to troubleshoot if problem occurs. 3. Test-points should be enhanced so that the connectors would fit and able to acquire the standard test-points for laboratory modules in circuit courses.
REFERENCES
[1] Krivicka s , R.V. and Krivickas , J . , The new college system of engineering Education in Lithuania. Proc. 7 Available: http://www.labvolt.com/products/electricity-and -electronics.
[2] Springer. Journal of Science Education and Technology, v18 n6 p546-555 Dec 2009, 233 Spring Street, New York, NY 10013, Available: http:// www.springerlink.com
[14] European Journal of Operational Research, 186(3), pp 893–914, Amsterdam-printed in Netherlands, 2nd Ed., Elsivier Scientific Publishing Company, 2008
[15] Sweet, Floyd A., “Introduction to Electric Circuits”., “Netherlands, 2nd Edition, Available:http://www.worldofelectronics.com/book/basic_circuits_theories.html
[17] Hasan Demirel, “Fundamentals of Electric Circuits 7th Edition", pp 43-44 Available:http://www.associatedcontent.com/book/1326622/basic_electrical_theory.html
[18] Sweet, Floyd A., “Introduction to Electric Circuits”., “Netherlands, 2nd Edition, Available:http://www.worldofelectronics.com/book/basic_circuits_theories.html
[19] Hasan Demirel, “Fundamentals of Electric Circuits 7th Edition", pp 88-89 Available:http://www.electronic-circuits.com/book/1326622/basic_electrical_theory.html
[20] Hasan Demirel, “Fundamentals of Electric Circuits 7th Edition", pp 112-113 Available:http://www.electronic-circuits.com/book/1326622/basic_electrical_theory.html
[21] Hasan Demirel, “Fundamentals of Electric Circuits 7th Edition", pp 156., Available:http://www.electronic-circuits.com/book/1326622/basic_electrical_theory.html
[22] Sweet, Floyd A., “Introduction to Electric Circuits”., “Netherlands, 2nd Edition, Available:http://www.worldofelectronics.com/book/basic_circuits_theories.html
[23] Hasan Demirel, “Fundamentals of Electric Circuits 7th Edition", pp 231-232., Available:http://www.electronic-circuits.com/book/1326622/basic_electrical_theory.html
[24] Hasan Demirel, “Fundamentals of Electric Circuits 7th Edition", pp 233., Available:http://www.electronic-circuits.com/book/1326622/basic_electrical_theory.html
[25] Holbert, Keith E.,“circuit analysis”,pp 112,.Available: http://www.circuit-analysis.com /articles/basic-electronics/143525/.html
[26] Sweet, Floyd A., “Introduction to Electric Circuits”., “Netherlands, 2nd Edition, Available:http://www.worldofelectronics.com/book/basic_circuits_theories.html
[27] Sweet, Floyd A., “Introduction to Electric Circuits”., “Netherlands, 2nd Edition, Available:http://www.worldofelectronics.com/book/basic_circuits_theories.html
[28] Holbert, Keith E.,“circuit analysis”,pp 122,.Available: http://www.circuit-analysis.com /articles/basic-electronics/143526/.html
[29] Sweet, Floyd A., “Introduction to Electric Circuits”., “Netherlands, 2nd Edition, Available:http://www.worldofelectronics.com/book/basic_circuits_theories.html
[30] Hasan Demirel, “Fundamentals of Electric Circuits 7th Edition", pp 265-266., Available:http://www.electronic-circuits.com/book/1326622/basic_electrical_theory.html
[31] Hasan Demirel, “Fundamentals of Electric Circuits 7th Edition", pp 268-269 Available:http://www.electronic-circuits.com/book/1326622/basic_electrical_theory.html
[32] Hasan Demirel, “Fundamentals of Electric Circuits 7th Edition", pp 302 Available:http://www.electronic-circuits.com/book/1326622/basic_electrical_theory.html
[33] Sweet, Floyd A., “Introduction to Electric Circuits”., “Netherlands, 2nd Edition, Available:http://www.worldofelectronics.com/book/basic_circuits_theories.html
Appendix A
St. Paul University Surigao
Surigao City
Engr. Robert R. Bacarro Dean of College of Engineering St. Paul University Surigao Surigao City
Dear Engr Bacarro:
Greeting of Peace!
The undersigned are in the process of conducting a research study entitled “Laboratory Modules for Circuit Courses in St. Paul University Surigao”, in partial fulfillment of the course Bachelor of Science in Electronics Engineering.
In order to gather data, an evaluation will be administered to the participants of the study.
In this regard, knowing your expertise in the field of statistics and research we may humbly present the questionnaire for validation.
Attached is the copy of the said evaluation sheet. In anticipation for the favorable action to this matter, thank you so much.
Sincerely Yours,
Abucejo, Jervic B. Antinopo, James Arbil E. Digamon, Rosie Gay S.
Approved By:
ENGR ROBERT R BACARRO Research Adviser/Dean of College of Engineering
Appendix B
St. Paul University Surigao
Surigao City
PERFORMANCE EVALUATION FORM FOR THE LABORATORY MODULES
Name: ________________ Field of Expertise: ________________Date: _______________
Kindly rate honestly your satisfaction with regards to the design project conducted by the researchers. The result will help the researchers evaluate the output of this study. This form will evaluate the system’s performance if it is acceptable or not to the field of experts.
The rating scale below:
4 – Very High 3 – High 2 – Low 1 – Very Low
| |Rating |
|Variables | |
| |4 |3 |2 |1 |
| 1.) EFFICIENCY: | | | | |
|Power consumption of the system | | | | |
|Time consumption in conducting an experiment | | | | |
|Users can work well with the system | | | | |
|Easy connection of test instruments into the modules | | | | |
| 2.) ACCURACY: | | | | |
|Measuring input data | | | | |
|Measuring output data | | | | |
|Measuring data in test points | | | | |
|Power source measurements | | | | |
| 3.) SENSITIVITY: | | | | |
|Working above and below the operating voltage | | | | |
|Working above and below room temperature | | | | |
|Working despite vibrations of the modules | | | | |
| 4.) DURABILITY: | | | | |
|Components placement in PCB | | | | |
|Design of the casing | | | | |
|Placement of the test points | | | | |
|Good wiring practice | | | | |
_________________________ Signature over Printed Name
Appendix C
St. Paul University Surigao
Surigao City
ACCEPTABILITY LEVEL EVALUATION FORM FOR
LABORATORY MODULES
Kindly rate honestly your acceptability with regards to the design project conducted by the researchers. The result will help the researchers evaluate the output of this study. This form will evaluate the system if it is acceptable or not to the possible users.
4 – Very High 3 – High 2 – Low 1 – Very Low
| |Rating |
|Variables | |
| |4 |3 |2 |1 |
|FUNCTIONALITY AND SUITABILITY: | | | | |
|Connectivity of the design to external device | | | | |
|Ease of gathering data from the design | | | | |
|Availability of terminals | | | | |
|PACKAGE DESIGN: | | | | |
|Durability of the case | | | | |
|Size of the case | | | | |
|Color of the case | | | | |
|Weight of the case | | | | |
|COST EFFECTIVENESS: | | | | |
|Cost of the casing | | | | |
|Cost of materials | | | | |
|Cost of the casing | | | | |
|Cost of materials | | | | |
________________________ Signature over Printed Name
Natural Responses of RC Circuit with DC Excitation, Module 6
[pic]
Natural Responses of RL Circuit with DC Excitation, Module 6
[pic]
Natural Responses of RLC Circuit with DC Excitation, Module 6
Circuit 2 Modules Resistive
[pic]
Capacitive [pic]
Inductive [pic]
Resistive, Capacitive and Inductive Circuits with Sinusoidal Excitation, Module 1
RL Circuit [pic]
RC Circuit [pic]
RLC Circuit [pic]
Impedance of a Series RLC Circuit, Module 2
RC Circuit [pic]
RL Circuit
[pic]
RLC Circuit [pic]
Impedance and Admittance of Parallel RLC Circuit, Module 3
Norton’s Theorem
[pic] [pic]
Thevenin’s Theorem
[pic] [pic]
Circuit Analysis for Network Theorems, Module 4
RL Circuit [pic]
RC Circuit [pic]
RLC Circuit [pic]
Power in AC Circuits, Module 5
RLC Circuit [pic]
RCL Circuit [pic]
Series Resonance, Module 6
RLC Circuit [pic]
RCL Circuit [pic] Parallel Resonance, Module 7
[pic]
Two Port Network Parameters, Module 8
LABORATORY MODULES FOR CIRCUIT COURSES
IN ST. PAUL UNIVERSITY SURIGAO
_____________________
A Thesis Presented to
The Faculty of the College of Engineering
St. Paul University Surigao
Surigao City
________________________
In Partial Fulfillment of the Requirements for the Degree
BACHELOR OF SCIENCE IN ELECTRONICS ENGINEERING
______________________
by
Abucejo, Jervic B.
Antinopo, James Arbil E. Digamon, Rosie Gay S.
March 2013
APPROVAL SHEET
This undergraduate thesis entitled
LABORATORY MODULES FOR CIRCUIT COURSES
IN ST. PAUL UNIVERSITY SURIGAO
Prepared and submitted by JERVIC B. ABUCEJO, JAMES ARBIL E. ANTINOPO and ROSIE GAY S. DIGAMON has been examined and is recommended for approval and acceptance for ORAL EXAMINATION.
ENGR. ROBERT R. BACARRO
Adviser
PANEL OF EXAMINERS
APPROVED by the committee on Oral Examination with the grade of 90% on February 5, 2013.
MRS. LOUREDIL F. LONGOS
Chair
ENGR. RUTH EPANES ENGR. ANGELUS VINCENT GUILALAS Member Member
ACCEPTED in Partial fulfillment of the requirements for the degree BACHELOR OF SCIENCE IN ELECTRONICS ENGINEERING
ENGR. ROBERT R. BACARRO
Dean, College of Engineering
APPENDIX D
CHED MEMORANDUM ORDER (CMO) No. 24 Series of 2008
SUBJECT : POLICIES AND STANDARDS FOR THE DEGREE OF BACHELOR OF SCIENCE IN ELECTRONICS ENGINEERING
---------------------------------------------------------------------------------------------------------------------
In accordance with the pertinent provisions of Republic Act (RA) No. 7722, otherwise known as the “Higher Education Act of 1994,“ Republic Act 9292 otherwise known as the “New Electronics Engineering (ECE) Law” and by virtue of Resolution No. 210-2008 of the Commission en banc dated May 5, 2008 and for the purpose of rationalizing the electronics and communications engineering education in the country, the following policies and standards are hereby adopted and promulgated by the Commission.
ARTICLE I – INTRODUCTION
Section 1. Rationale
Electronics Engineering is a branch of engineering that integrates available and emerging technologies with knowledge of mathematics, natural, social and applied sciences to conceptualize, design, and implement new, improved, or innovative electronic, computer and communication systems, devices, goods, services and processes.
An Electronics Engineer is endowed with spiritual, moral, and ethical values, mindful of safety concerns and guided with responsibility to society an environment in the discharge of his functions.
The herein Policies and Standards (PS) have been reviewed in accordance with recent approved CMOs, industry needs, latest trends and technology in the field of Electronics Engineering. The revision of the PS for BSECE program emerged as a result of consolidated effort of the academe, industry and other concerned agencies.
ARTICLE II - AUTHORITY TO OPERATE
Section II The BSECE program shall be operated only by HEIs with proper authority granted by the Commission on Higher Education (CHED) or by the respective Boards in case of chartered State Universities and Colleges (SUCs) and Local Colleges and Universities (LCUs).
ARTICLE III -PROGRAM SPECIFICATION
Section 3. Degree Name
The program herein shall be called BACHELOR OF SCIENCE IN ELECTRONICS ENGINEERING (BSECE).
Section 4. Program Description
4.1 Objectives
a. Provide the student with an education in the fundamentals of electronics engineering that will allow him to be immediately competitive in industry or in graduate work while providing him with the best opportunity for achieving his full potential during his lifetime. b. Develop a sense of professional responsibility and social awareness. c. Provide practical applications as evidenced by laboratory, design, project study, computer exercises and practicum courses. These would help the student to work well whether independently or as part of a group.
4.2 Program Outcomes
A graduate of the Bachelor of Science in Electronics Engineering ( ECE) program must attain:
a. Ability to apply knowledge of mathematics, physical, life and information sciences; and engineering sciences appropriate to the field of practice. b. Ability to design and conduct experiments, as well as to analyze and interpret data.
c. Ability to design a system, component, or process to meet desired needs within identified constraints. d. Ability to work effectively in multi-disciplinary and multi-cultural teams. e. Ability to recognize, formulate, and solve engineering problems. f. Recognition of professional, social, and ethical responsibility. g. Ability to effectively communicate orally and in writing using the English language. h. Understanding of the effects of engineering solutions in a comprehensive context.
ANNEX IV B –LABORATORY REQUIREMENTS I - ECE LABORATORY
|CIRCUIT 1 |CIRCUIT 2 |
|1. Analysis of Resistive Networks |1. Resistive, Capacitive and Inductive |
|- Series Circuit |Circuits with Sinusoidal Excitation |
|- Parallel Circuit |Purely resistive circuit |
|- Series-parallel Circuit |Purely capacitive circuit |
| |Purely inductive circuit |
|2. Resistance Bridge Circuit | 2. Impedance of Series RLC Circuit |
|- Wheatstone Bridge Circuit |- RL Circuit |
| |- RC Circuit |
| |- RLC Circuit |
| 3. Mesh Analysis and Nodal Analysis |3. Impedance and Admittance of |
| |Parallel RLC Circuit |
| |- RL Circuit |
| |- RC Circuit |
| |- RLC Circuit |
|4. Superposition Theorem and Linearity |4. Circuit Analysis for Network |
|Theorem |Theorems |
| |- Norton’s Theorem |
| |- Thevenin’s Theorem |
|5. Thevenin’s Theorem and Linearity |5. Power in AC Circuit |
|Theorem |- RC Circuit |
| |- RL Circuit |
| |- RLC Circuit |
|6. Natural Responses of RC Circuit with |6. Series Resonance |
|DC Excitation |- RLC Circuit |
| |- RCL Circuit |
|7. Natural Responses of RL Circuit with |7. Parallel Resonance |
|DC Excitation |- RLC Circuit |
| |- RCL Circuit |
|8. Natural Responses of RLC Circuit with |8. Two-port Network Parameters |
|DC Excitation | |
Appendix F
Laboratory Experiment Guide
EXPERIMENT # 1
ANALYSIS OF RESISTIVE NETWORKS
OBJECTIVES To study the effect of resistors connected in series, in parallel, and a series-parallel network. This will be accomplished by first analyzing the particular circuits to be used in this experiment numerically in the preliminary lab exercise.
EQUIPMENTS Laboratory Module (JJARG 1-1) Multi-tester Connectors Power Supply
PROCEDURES Series Circuit The circuit shown in the following Figure 1 will be used to investigate the concept of voltage division. Series Circuit
[pic]
Figure 1 1. Measure the equivalent resistance in theoretical aspect before the voltage source is connected to the circuit. 2. Connect the voltage supply to the resistive network. Set the voltage supply to 9V. 3. Set the multi-tester into voltmeter mode and measure the voltages across each resistor V1, V2, and V3. To measure source current (Is), set the multi-tester into ammeter mode and connect it in the test points (OC). Record the data in table 1. 4. Measure theoretical values based on Ohm’s Law. 5. Compare the theoretical value to experimental value and record the data in table 1. 6. Calculate the percentage of error given %Error = [pic] x 100% 7. Connect the voltage supply to the resistive network. Now, set the voltage supply to 12V. 8. Repeat steps 3 to 6.
Parallel Circuit The circuit shown in the following Figure 2 will be used to investigate the concept of current division. Parallel Circuit
[pic]
Figure 2 1. Measure the equivalent resistance in theoretical aspect before the voltage source is connected to the circuit. 2. Connect the voltage supply to the resistive network. Set the voltage supply to 9V. 3. Set the multi-tester into ammeter mode and measure the currents I1, I2, and I3 in the test- points (OC). To measure voltage (V), set the multi-tester into voltmeter mode and measure the voltage (V) across (R3). Record the data in table 2. 4. Measure theoretical values based on Ohm’s Law. 5. Compare the theoretical value to experimental value and record the data in table 2. 6. Calculate the percentage of error given %Error = [pic] x 100% 7. Connect the voltage supply to the resistive network. Now, set the voltage supply to 12V. 8. Repeat steps 3 to 6.
Series-Parallel Circuit The circuit shown in the following Figure 3 will be used to determine the voltage across and the current through each resistor as well as the effect of open-circuiting and short-circuiting one resistor. Series-Parallel Circuit
[pic]
Figure 3 1. Measure the equivalent resistance before the voltage source is connected to the circuit. 2. Connect the voltage supply to the resistive network. Set the voltage supply to 9V.
3. Measure the voltages V1 and V2 across R2 and R5 by connecting voltmeter to the test points. Measure the currents I1, I2, and I3 in the test-points (OC). Record the data in table 3. 4. Measure theoretical values based on Ohm’s Law. 5. Compare the theoretical value to experimental value and record the data in table 3. 6. Calculate the percentage of error given %Error = [pic] x 100% 7. Connect the voltage supply to the resistive network. Now, set the voltage supply to 9V. 8. Repeat steps 3 to 6.
OBJECTIVE To illustrate the role of series resistors in form of a voltage divider circuit.
EQUIPMENTS Laboratory Module (JJARG 1-2) Multi-tester Connectors Power Supply
PROCEDURES
Analyze the Wheatstone bridge given below. Although the Wheatstone bridge can be operated in DC and AC mode, we will use a 5V DC power source. The circle with an ‘A’ in it represents an ammeter and it connects the two voltage dividers together. When no current flows through the ammeter, the Wheatstone bridge circuit is said to be “balanced” and when there is current flows through the ammeter, the Wheatstone bridge circuit is said to be “unbalanced”. Use the voltage power supply source on the laboratory module. In the Wheatstone bridge we set up two voltage dividers as illustrated below in figure 1.
[pic]
Figure 1 1. Measure the equivalent resistance before the voltage source is connected to the circuit. 2. Connect the voltage supply to the resistive network. Set the voltage supply to 5 V. 3. Set the multi-tester to ammeter mode and measure current to the test points in open-circuit (OC) and record the data. 4. Determine wheather the circuit is balanced or unbalanced.
OBJECTIVES The purpose of this experiment was to build two resistor circuits, and measure the voltage and current at each component, and the node voltages to illustrate the concepts of nodal and mesh analysis, then analyze the results by comparing them to the theoretical calculations.
THEORY Nodal analysis is a method of calculating the voltage at each node in a circuit. This is accomplished by setting up a set of equations which are based on Kirchhoff’s current law for each node. These equations are then solved simultaneously to find the node voltages. The following is the procedure for applying nodal analysis to a circuit: 1) Select a node as the reference node. Assign voltages (v1, v2, v3, etc.) to the remaining nodes. The voltages are referenced with respect to the reference node. 2) Apply Kirchhoff’s current law (Σi=0) to each of the non-reference nodes. Use Ohm’s law (v=iR) to express the branch currents in terms of node voltages. 3) Solve the resulting simultaneous equations to obtain the unknown node voltages. Mesh analysis is a method of calculating the currents in each branch of a circuit. This is accomplished by setting up a set of equations which are based on Kirchhoff’s voltage law for each loop (or mesh) in the circuit. The solution of the set of equations results in the currents through each element in the circuit. The following is the procedure for applying mesh analysis to a circuit: 1) Assign mesh currents (i1, i2, i3, etc.) to each mesh (loop) in the circuit. 2) Apply Kirchhoff’s voltage law (Σv=0) to each of the meshes. Use Ohm’s law (v=iR) to express the voltages in terms of the mesh currents. 3) Solve the resulting simultaneous equations to obtain the unknown mesh currents.
EQUIPMENTS Laboratory Module (JJARG 1-1) Multi-tester Connectors Power Supply
PROCEDURES
1. Measure the equivalent resistance before the voltage source is connected to the circuit. 2. Connect the variable output power supply to the resistive network for figure 1. Set the voltage supply to 5V and 9V. 3. Connect a voltmeter at each node, with reference to the reference node. To measure voltages V1, V2, V3 and V4. Record the voltage measured.
4. Connect an ammeter in open-circuit (OC) in each branch and record the measured current. 5. Compare the theoretical value to experimental value to get the percentage of error given %Error = [pic] x 100%. 6. Repeat all steps for figure 2.
[pic]
Figure 1
[pic]
Figure 2 DATA REPRESENTATION Figure1 Table 1.1
|NODE |CALCULATED VOLTAGE |MEASURED VOLTAGE |% OF ERROR |
|1 | | | |
|2 | | | |
|3 | | | |
|4 | | | |
Table 1.2
|BRANCH |CALCULATED CURRENT |MEASURED CURRENT |% OF ERROR |
|1 | | | |
|2 | | | |
|3 | | | |
Table 2.2
|BRANCH |CALCULATED CURRENT |MEASURED CURRENT |% OF ERROR |
|1 | | | |
|2 | | | |
|3 | | | |
OBSERVATIONS
CONCLUSION
EXPERIMENT # 4
SUPERPOSITION AND LINEARITY THEOREM
OBJECTIVES 1. To measure circuit parameters to determine if they are linearly related. 2. To verify the superposition theorem. 3. To determine the importance of these theorems.
EQUIPMENTS Laboratory Module (JJARG 1-4) Multi-tester Connectors Power Supply
PROCEDURES LINEARITY 1. Given the linear circuit below in figure 1.
[pic]
Figure 1. Linearity
2. At 3 different voltages of Vin between 5Vand 12V, measure the output voltage (Vout) across resistor R5. 3. Calculate the linearity constant that relates the output voltage to the input voltage. 4. Record your data in Table 1.
SUPERPOSITION 1. We will now verify the superposition circuit in figure 2, A and B. 2. Connect the voltage supply to the resistive network. Set the voltage power supply between 5 V and 12V. 3. Measure the voltage across the resistor R2 and record the data in table 2.
QUESTIONS 1. For the circuit of Figure 1, how did the measurements made in the lab compare to the predicted values calculated using linearity ? Explain any differences.
2. For each of the two circuits you built for the superposition theorem, how well did the calculated value from the lab compare to the measured outputs? Explain any differences.
3. If each of the voltage supplies were independently increased in magnitude (not polarity) by 1V, which one would have a bigger effect on the change in the output voltage? Explain your results.
OBSERVATIONS
CONCLUSION
EXPERIMENT # 5
THEVENIN’S AND NORTON’S THEOREM
OBJECTIVES 1. To develop circuit construction skills in dc circuit voltage and current measurement skills. 2. To determine the characteristics of Thevenin and Norton’s theorem. 3. To study the principle of these two theorems.
EQUIPMENTS Laboratory Module (JJARG 1-5) Multi-tester Connectors Power Supply
PROCEDURES 1. Given the circuit shown in Figure 1.
[pic]
Figure 1 2. Connect the variable voltage power supply to the circuit and set the voltage supply between 5V and 12V. 3. Connects an voltmeter across 10kohm to measure the voltage, Vab. 4. Record the value of Vab. 5. Remove the 10kΩ resistor from the circuit in Figure 1. Connect an ammeter in open-circuit (OC) between points a and b as shown in Figure 2 and measure the short circuit current, Isc. Record the value in Table 1. Note the positive direction of current flow.
[pic]
6. Measure the Thevenin's open circuit voltage, Voc, for the remaining circuit. Figure 2 shows the circuit used to make the open circuit voltage measurements.
DATA REPRESENTATION
|Input Voltage |Output Voltage in points A & B |Open-circuit Voltage |Current for short circuit |
|Vin (V) |VAB (V) | |ISC (A) |
| | |VOC (V) | |
|5 | | | |
|9 | | | |
|12 | | | |
OBSERVATIONS
CONCLUSION
EXPERIMENT # 6
NATURAL RESPONSES OF RC CIRCUITS WITH DC EXCITATION
OBJECTIVES 1. To study the characteristic of a capacitor as an energy storing elements. 2. To demonstrate the circuit as charging and discharging cycle. 3. To measure the time constant for the decay, t = RC.
EQUIPMENTS Laboratory Module (JJARG 1-6) Multi-tester Connectors Power Supply
PROCEDURES 1. Calculate the time constant of the circuit below before the input source is connected to the circuit. For the charging cycle the capacitor voltage is given by VC=V0(1-e-t/τ) and for the discharging cycle it is given by VC=V0e-t/τ. Record it in table 1. 2. Given the circuit shown in figure 1. Connect the power supply as an input source and measure the output voltage.
[pic]
Figure 1 3. Switch on the circuit on charge cycle, were resistor is connected to S1. Measure the capacitor voltage (Vc) as a function of time and record the value in table 1. 4. For discharging cycle, switch on the circuit on discharge state, were resistor is connected to S2 and record the data in table 1. 5. Measure current transient I= (E/R)e -t/τ .
2. How do you get a short/long time constant in an RC circuit?
3. What happens to the output of the circuit immediately after the switch is closed? Explain.
4. What happens to the output of the circuit immediately after the switch is opened? Explain.
OBSERVATIONS
CONCLUSION
EXPERIMENT # 7
NATURAL RESPONSES OF RL CIRCUITS WITH DC EXCITATION
OBJECTIVES 1. To study the characteristic of an inductor as an energy storing elements. 2. To demonstrate the circuit as charging and discharging cycle. 3. To measure the time constant for the decay, t = R/L.
EQUIPMENTS Laboratory Module (JJARG 1-6) Multi-tester Connectors Power Supply
PROCEDURES 1. Calculate the time constant of the circuit below in before the input source is connected to the circuit. For the charging cycle the inductor voltage is given by VL=V0(1-e(-R/L)t) and for the discharging cycle it is given by VL=V0e-t/RL. Record it in table 1. 2. Given the circuit shown in figure 1. Connect the power supply as an input source and measure the output voltage. 3. Switch on the circuit on charge cycle, were resistor is connected to S1. Measure the inductor voltage (VL) as a function of time and record the value in table 1.
[pic]
Figure 1 4. For discharging cycle, switch on the circuit on discharge state, were resistor is connected to S2 and record the data in table 1. 5. Measure current transient I= (E/R)(1-e(-R/L)t).
2. How do you get a short/long time constant in an RL circuit?
3. What happens to the output of the circuit immediately after the switch is closed? Explain.
4. What happens to the output of the circuit immediately after the switch is opened? Explain.
OBSERVATIONS
CONCLUSION
EXPERIMENT # 8
NATURAL RESPONSES OF RLC CIRCUITS WITH DC EXCITATION
OBJECTIVES 1. To study the characteristic of both inductor and capacitor as an energy storing elements. 2. To demonstrate the RLC circuit as charging or discharging cycle. 3. To determine the opposing responses to a voltage when applied at t=0 and when t=infinity. THEORY: The conditions for series RLC: (1) @ t = 0; i = 0 (2) @ t = 0; L (di/dt) = E
EQUIPMENTS Laboratory Module (JJARG 1-6) Multi-tester Connectors Power Supply
PROCEDURES 1. Calculate the current (i) when the case is over damped (R/2L)2 > 1/LC, when critically damped (R/2L)2 = 1/LC, and under damped (R/2L)2 < 1/LC. Record it in table 1. 2. Given the circuit shown in figure 1. Connect the power supply as an input source and measure the output voltage. 3. Switch on the circuit on charge cycle, were resistor is connected to S1. Measure the voltage as a function of time and record the value in table 1.
[pic]
4. For discharging cycle, switch on the circuit on discharge state, were resistor is connected to S2 and record the data in table 1. 5. Measure the value of alpha ([pic]) and beta [pic].
1. In previous experiments regarding charging an discharging an capacitor and inductor, is there a difference in their outputs if both of them is connected or not? Explain.
2. How do you get a short/long time constant in an RLC circuit?
3. What happens to the output of the circuit immediately after the switch is closed? Explain.
OBSSERVATIONS
CONCLUSION
EXPERIMENT # 1
RESISTIVE, INDUCTIVE AND CAPACITIVE CIRCUITS WITH SINUSOIDAL EXCITATION
OBJECTIVES 1. To study series resistive, capacitive and inductive circuits and their sinusoidal steady state behaviour. 2. To calculate sinusoidal voltage and current source (independent or dependent) produces a voltage or current that varies sinusoidal with time.
EQUIPMENTS Signal Generator Oscilloscope Laboratory Module (JJARG 2-1) Multi-tester Connectors
PROCEDURES Resistive Circuit 1. Given the circuit in below in figure 1, connect the function generator as the source of the circuit below and set it in 1 KHz. Set the function generator to sine wave mode. 2. Measure the current in open-circuit (OC) and voltage, in test points A and B of the circuit. 3. Calculate the resonance of the circuit. Given [pic] and f= [pic]. 4. Plot the output signal of the circuit. 5. Set frequency range into 3 KHz and 5 KHz and repeat steps 2, 3 and 4.
Resistive
[pic]
Figure 1
Capacitive Circuit 1. Given the circuit in below in figure 2, connect the function generator as the source of the circuit below and set it in 1 KHz. Set the function generator to sine wave mode. 2. Measure the current in open-circuit (OC) and voltage, in test points A and B of the circuit. 3. Calculate the resonance of the circuit. Given [pic] and f= [pic] 4. Plot the output signal of the circuit. 5. Set frequency range into 3 KHz and 5 KHz and repeat steps 2, 3 and 4.
Capacitive [pic]
Figure 2
Inductive Circuit 1. Given the circuit in below in figure 3, connect the function generator as the source of the circuit below and set it in 1 KHz. Set the function generator to sine wave mode. 2. Measure the current in open-circuit (OC) and voltage, in test points A and B of the circuit. 3. Calculate the resonance of the circuit. Given [pic] and f= [pic] 4. Plot the output signal of the circuit. 5. Set frequency range into 3 KHz and 5 KHz and repeat steps 2, 3 and 4.
QUESTIONS 1. Among the three circuits, which one presents a good output? Explain.
2. What are the values of sinusoidal voltage and current for each of the circuit?
3. Explain briefly, why purely resistive and capacitive circuit has almost the same outputs?
OBSERVATION
CONCLUSION
EXPERIMENT # 2
IMPEDANCE OF A SERIES RLC CIRCUIT
OBJECTIVES 1. To study the behaviour of an RLC series circuit in their sinusoidal steady state behaviour. 2. To measure the circuit current and the voltage across the resistor. 3. To determine the maximum and minimum impedance of a series RLC circuit.
EQUIPMENTS Signal Generator Oscilloscope Laboratory Module (JJARG 2-2) Multi-tester Connectors
PROCEDURES 1. Given the circuit in below in figure 1, connect the function generator as the source of the circuit below and set it in 1 KHz. Set the function generator to sine wave mode. 2. Measure the current in open-circuit (OC) and voltage, in test points A and B of the circuit. 3. Calculate the resonance of the circuit. Given [pic] and f= [pic] and the value of impedance Z. 4. Record the data in table 1. 5. Set frequency range into 3 KHz and 5 KHz and repeat steps 2, 3 and 4. 6. Repeat steps 1, 2, 3 and 5 for figures 2 and 3. Record the data in tables 2 and 3.
QUESTIONS 1. In what aspect those resonance occur in a series RLC circuit?
2. In a series RLC circuit, what quantity is maximum at resonance and why?
3. Based on the value of inductor and capacitor. Calculate the resonance frequency of series RLC circuit.
4. What is the value for measured voltage (Vmeas) and current (Imeas)? In
OBSERVATION
CONCLUSION
EXPERIMENT # 3
IMPEDANCE AND ADMITTANCE OF A PARALLEL CIRCUIT
OBJECTIVES 1. To study the behaviour of an RLC parallel circuit in their sinusoidal steady state behaviour. 2. To demonstrate the effect of frequency changes in a parallel RLC circuit. 3. To measure the impedance and admittance of a parallel RLC circuit.
EQUIPMENTS Signal Generator Oscilloscope Laboratory Module (JJARG 2-3) Multi-tester Connectors
PROCEDURES 1. Given the circuit in below in figure 1, set the function generator into sine wave form and connect as the source of the circuit below and set it in 1 KHz. 2. Measure the current in open-circuit (OC) and voltage in test points A and B of the circuit. 3. Calculate the admittance of the circuit, Given admittance[pic]; where G = [pic] and B =[pic]. 4. Plot the output signal of the circuit. 5. Set frequency range into 3 KHz and 5 KHz and repeat steps 2, 3 and 4. 6. Repeat steps 1, 2, 4 and 5 for figures 2 and 3. Record the data in table 2 and 3.
QUESTIONS 1. What is the significant relationship between impedance and admittance in a parallel RLC circuit?
2. What is the admittance value in parallel RLC circuit?
3. Based on the value of capacitance and the sinusoidal frequency, calculate the capacitive susceptance (Bc) of the capacitor. Given Bc = 2[pic]FC.
4. Based on the value of inductance and the sinusoidal frequency, calculate the inductive susceptance (BL) of the inductor. Given BL = 2[pic]FL.
5. What is the phase difference[pic] between the ac rms voltage across the parallel circuit and the rms current entering the parallel where, [pic] = arctan ([pic]) .
OBSERVATION
CONCLUSION
EXPERIMENT # 4
CIRCUIT ANALYSIS FOR NETWORK THEOREMS
OBJECTIVES 1. To develop circuit construction skills in sinusoidal measurement skills. 2. To study the behaviour of a network theorems circuit in sinusoidal steady state condition. 3. To determine the importance of these theorems.
EQUIPMENTS Signal Generator Oscilloscope Laboratory Module (JJARG 2-4) Multi-tester Connectors
PROCEDURES 1. Given the circuit shown in Figure 1. 2. Connect the function generator to the circuit and set the frequency range into 1kHz. Set the function generator to sine wave mode. Record the data in table 1. 3. Connect an voltmeter across the 10kΩ resistor to measure voltage at point A and B (Vab). 4. Record the value of Vab. 5. Set frequency range into 3 KHz and 5 KHz and repeat steps 3 and 4. Record the data. 6. Remove the 10kΩ resistor from the circuit in Figure 1. Connect an ammeter and oscilloscope between the points a and b as shown in Figure 1.1 and measure the short circuit current, Isc. Record the value in Table 1. Note the positive direction of current flow. 7. Repeat steps 3, 4 and 5.
Norton’s Theorem
[pic]
Figure 1 1. We will now verify the superposition circuit in figure 2, A and B 2. Connect the function generator to the resistive network. Set the function generator into 1kHz 3. Measure the voltage across the R2 resistor. Record the data in table 2. 4. Set frequency range into 3 KHz and 5 KHz and repeat steps 3 and 4. Record the data. 5. Repeat step 3 and record the data.
To determine the real, reactive and apparent power and the power factor for a series RC, RL, and RLC circuit.
THEORY
[pic]
EQUIPMENTS Signal Generator Oscilloscope Laboratory Module (JJARG 2-5) Multi-tester Connectors
PROCEDURES
1. Given the circuit shown in Figure 1. 2. Connect the function generator to the circuit and set the frequency range into 1kHz. Set the function generator to sine wave mode. Record the data in table 1. 3. Connect a voltmeter across the inductor to measure voltage and the current in open-circuit (OC). 4. Set the function generator between 3kHz and 5kHz. Repeat step 3. 5. Calculate the real, reactive and apparent power and the power factor for RL circuit. 6. Repeat steps 2 to 5 for RC and RLC circuit.
OBJECTIVES 1. To experimentally find the resonant frequency of an series RLC circuit, and to compare it with the value predicted using the inductance and capacitance in the circuit. 2. To study the behaviour of the current, the inductive reactance, and the capacitive reactance in the vicinity of resonance.
THEORY The peak voltage across each element is given by: VR = imaxR VC = imaxXC, where XC is the capacitive reactance VL = imaxXL, where XL is the inductive reactance For the phase relations between these voltages, the peak voltage of the AC source is given by: Vmax = imaxZ where Z is the impedance of the circuit in ohms (Ω). [pic] where XL = 2πfL, XC = 1/(2πfC), and R is the resistance in the circuit. The resonant frequency is given [pic].
EQUIPMENTS Signal Generator Oscilloscope Laboratory Module (JJARG 2-6) Multi-tester Connectors
PROCEDURES 1. Given the circuit shown in Figure 1. 2. Connect the function generator to the circuit and set the frequency range into 1kHz and set the function generator to sine wave mode. Record the data in table 1. 3. Connect an ammeter to the open-circuit to measure the current that flows in a series RLC circuit. 4. Set the function generator between 3kHz and 5kHz. Repeat step 3. 5. Calculate the impedance, capacitive reactance, inductive reactance and the resonant frequency. 6. Repeat steps 2 to 5 for parallel RCL circuit in figure 2 and record the data in table 2.
OBJECTIVES 1. To experimentally find the resonant frequency of an series RLC circuit, and to compare it with the value predicted using the inductance and capacitance in the circuit. 2. To determine the phase relationship between the voltage and current of a parallel resonant circuit at resonant frequency.
THEORY A parallel resonant circuit consists of a capacitor in parallel with an inductor and is often referred to as tank circuit. When XL = XC at the resonant frequency, the inductor current IL and capacitor current IC are equal in magnitude and 180 degrees out-of-phase. Therefore the impedance f a parallel resonant circuit at resonant frequency is equal to Rp and the phase between the voltages across the tank circuit and the current entering the tank circuit is 0 degrees. Therefore Z = Rp and phase = 0 degrees.
EQUIPMENTS Signal Generator Oscilloscope Laboratory Module (JJARG 2-7) Multi-tester Connectors
PROCEDURES
1. Given the circuit shown in Figure 1, connect the function generator to the circuit and set the frequency range into 1kHz. Record the data in table 1. 2. Determine the quality factor (Q) of a parallel resonant circuit. 3. Connect an ammeter to the open-circuit to measure the current that flows in a parallel RLC circuit. 4. Set the function generator between 3kHz and 5kHz. Repeat step 3. 5. Calculate the impedance, capacitive reactance, inductive reactance and the resonant frequency. 6. Repeat steps 2 to 5 for RCL circuit in figure 2 and record the data in table 2.
OBJECTIVES To classify the set of y-parameters of a two-port network.
THEORY A parallel resonant circuit consists of a capacitor in parallel with an inductor and is often referred to as tank circuit. When XL = XC at the resonant frequency, the inductor current IL and capacitor current IC are equal in magnitude and 180 degrees out-of-phase. Therefore the impedance f a parallel resonant circuit at resonant frequency is equal to Rp and the phase between the voltages across the tank circuit and the current entering the tank circuit is 0 degrees. Therefore Z = Rp and phase = 0 degrees.
EQUIPMENTS Signal Generator Oscilloscope Laboratory Module (JJARG 2-8) Multi-tester Connectors
PROCEDURES 1. First, measure the resistor values needed to build the circuit as given the circuit below and record the data in table 1.
[pic]
Figure 1
2. Calculate the impedance at various ports (aa’, bb’ and cc’). 3. Measure the voltages and currents to solve for the y-parameter.
DATA REPRESENTATION Table 1. Impedance measured at various two terminals of a one-port network
