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Java Applets for Microelectronics Education

Ralph M. Ford, Member, IEEE, Jonathan Bondzie, and Paul Kitcho

Abstract - This work describes a library of online courseware utilizing Java applets developed for Microelectronics education. The objective is to provide an online learning environment that supplements resident instruction. Java applets are utilized to interactively demonstrate principles, provide design tools, and allow students to test their knowledge via online quizzes. The course material and Java applets are included on the CD-ROM.

I. Introduction

The benefits of interactive multimedia courseware for engineering education are well established [1-5]. However, one has to spend only a short period of time reviewing course webpages to realize that much of the online material is not interactive. The primary use is to transmit information, such as assignments, solutions, and syllabi, to students. Other interactive opportunities, such as class bulletin boards, are available, but less common. These resources are valuable, but fail to fully utilize the interactive capabilities provided by the Java programming language.

Java, produced and freely distributed by Sun Microsystems [6], is an object-oriented programming language that is capable of producing both standalone applications and applets. Applets are programs that are embedded in HTML code, transmitted over a network, and run on a browser. Applets are platform independent, as long as the end-users have a Java compatible browser running on their platform. Since applets are programs, they provide the opportunity for user interactivity. In fact, the Java language was developed with this goal in mind; the graphical user interface and graphical objects are relatively easy to program. These characteristics make Java an ideal platform for developing and distributing educational applications, as indicated in the work by Chirico et. al. [7].

An obstacle that hinders educators from fully utilizing web-based teaching strategies is the amount of time and resources necessary to develop Java applets and associated HTML content. Software packages, such as Blackboard.com [8], Cyberprof and the Mallard learning environment [9], are expanding options for web-based course delivery. They typically provide functionality for creating assignments, grade reporting, interactive quizzes, newsgroups, and forums for student-teacher communication. They also allow the inclusion of Java applets. This underscores the need to develop high quality Java applets for distribution to engineering educators. Efforts to develop such applets are emerging. Wie [10] developed a library of applets for Solid State materials instruction that is available on the web. In addition, the School of Electrical and Computer Engineering at Georgia Tech has undertaken Computer Enhanced Education Initiative [11] and this includes developing educational Java applets [12].

This paper describes Java applets and associated instructional content developed to improve Microelectronics instruction. Results, based on student evaluation of the material, are included.

II. Microelectronics Instruction

Microelectronics is a required core course in nearly every electrical and computer engineering curriculum. Electrical and computer engineers need a solid understanding of how to analyze and design circuits containing microelectronic devices (op amps, diodes, and transistors). Although many of the concepts are not extremely difficulty to visualize, the content is rich in design and associated tradeoffs. Many of the tradeoffs are complex due to the nonlinear nature of the devices used. One example is zener diode voltage regulator design. In this case, there are multiple variables that affect the output ripple voltage. The tradeoffs between the parameters can be effectively demonstrated by an interactive Java applet that allows the user to experimentally minimize the ripple voltage.

At Penn State Erie, a two semester sequence in Microelectronics, utilizing the popular text Microelectronic Circuits by Sedra and Smith [13], is offered. Electrical engineers are required to complete both courses and computer engineers are required to complete the first course. The Sedra and Smith text is packaged with a CD-ROM containing a limited number of interactive examples. It is essentially a closed system; the examples cannot be incorporated into webpages. We have developed a library of Java applets and supporting webpages to supplement these courses. The applets are utilized to graphically illustrate concepts, to provide design tools, and for online quizzes.

III. Courseware Description

A series of HTML webpage lessons were developed that focus on practical applications of the material and problem-solving. Each typically contains the following sections:

Motivation & Web Resources. Provides motivation with practical applications of the material. Links to web resources are provided for further exploration.
Learning Objectives. A list of the objectives for the given module and associated textbook sections.
Theory. A short overview of the theory. In-depth theoretical development was left out in favor of lecture and textbook presentation.
Practice: How to solve problems. Provides problem solving techniques and hints for solving the associated problems.
Example Problem Applet. A step-by-step solution to an example problem.
Demonstration or Design Applet. Demonstration applets allow interactive exploration of selected concepts. The design applets allow the student to interactively design selected microelectronic circuits and observe the tradeoffs involved.
Interactive Quiz Applet. A quiz with hints and feedback to allow students to test their knowledge.
Survey. Allows the student to anonymously assess the effectiveness of the material.

Students can explore the sections in any order they choose, but the recommended flow is in the order presented. The lessons supplement the lecture and textbook material and are not intended to teach the material from the ground up.

The design applets, demonstration applets, and quiz applets are available and accessible from the following link:

Online version

The remainder of this section is an overview of the applets developed.

A. Design Applet: Zener Voltage Regulator

This applet provides the ability to interactively design the zener shunt regulator as shown in Fig. 1. The user can vary the DC and sinewave input sources (to model the transformer and rectifier), can select a real-world zener diode, and can select the shunt and load resistances. The DC and ripple output voltages are computed based on the user selections allowing exploration of the tradeoffs.

B. Design Applets: BJT DC Biasing

These applets provides the ability to experimentally compute the DC bias of npn transistor circuits as shown in Fig. 2. The user selects the DC voltage sources, resistance values, and the transistor beta value. The node voltages, branch currents, and mode of operation are computed. Exercises encourage the student to design circuits that meet a given specification and to explore the mechanisms that cause a transition between active and saturation modes.

Fig. 1. Voltage regulator design applet.

Fig 2. Transistor biasing applet.

C. Design Applets: Amplifier Design

These applets allow interactive design of the standard common emitter transistor amplifier configuration (Fig. 3). The user selects the transistor model and circuit components. The amplifier voltage gain, input resistance, output resistance, signal swing, and bandwidth are computed allowing exploration of design options.

Fig. 3. Common emitter design tool applet.

D. Design Applets: Frequency Response

The first of these applets, shown in Fig. 4, is a Bode plotter. It allows placement of poles and zeros at different frequencies and it plots both the magnitude and phase of the transfer function. In addition, it plots the individual contributions that arise due to each pole and zero. This is analogous to the method typically taught for constructing Bode plots and is an effective way for students to understand and practice this technique.

The second applet (Fig. 5) allows placement of poles and zeros in the complex plane and produces a frequency response plot for the system modeled. The user can move the poles and zeros in the complex plane and see the effect on the frequency response in real-time. This also allows for the design of filters using the pole/zero placement method.

Fig 4. Bode plotter applet.

Fig. 5. Pole/zero plotter applet.

E. Demonstration Applets

These applets are ulitized to graphically demonstrate concepts and illustrate problem-solving techniques. For example, the first demonstration applet (Fig. 6) in the library graphically shows how nonlinear devices are used as linear amplifiers. The tradeoffs involved in bias point selection and input signal magnitude are illustrated, and the user is able to visually determine when the linear assumption fails. There are also slideshow applets that provide step-by-step illustrations of concepts and problem solving techniques.

Fig 6. Small signal amplifier demonstration.

F. Quiz Applets

As part of this work, we developed a series of online quizzes in the form of Java applets. The types of questions allowed are multiple-choice, true-false, and fill-in-the-blank. The quizzes also provide for inclusion of hints and graphics.Quiz applets, illustrated in Fig. 7, provide the opportunity for students to test their problem solving abilities.

Fig. 7. Quiz applet.

IV. Results

Currently, students are encouraged, but not required, to utilize the web-based material and complete the surveys. Feedback from the surveys is utilized to improve the content and presentation of the material. For instance, early on in the project student feedback indicated that a sequential layout of the material was not effective. This led to the presentation format described in Section III.

At the end of the semester an anonymous survey was conducted to assess the usefulness of the material. Fourteen of the nineteen students in the class utilized the online material and completed the survey. Among these fourteen students, the average number of class homepage visits per student was ~1.75 times per week. The utility of the information on the class homepage was assessed, and the results are tabulated in Table I. It is clear that informational items that are updated an ongoing basis are utilized the most. A Question and Answer Board that was regularly monitored by the instructor was heavily used, and static information, such as the syllabus, was used very little.

TABLE I
Survey Results: Utility of class Webpage content.

Class Webpage Item	Useful	Somewhat Useful	Never Used
Class announcements	53.8%	38.5%	7.7%
What is Due and When ?	71.4%	21.4%	7.2%
Homework Problem Sets	42.9%	50%	7.2%
Question and Answer Board	50%	35.7%	14.3%
Syllabus	14.3%	14.3%	71.4%
Class Schedule	14.3%	42.9%	42.9%

The overall effectiveness of the online lessons was assessed and the results are shown in Table II. Each lesson was used by an average of eight students, with the maximum usage for a given lesson being eleven and the minimum four. The results indicate that 67% of the students who used the online courseware thought that it improved their understanding of the material and their grade. The applets were utilized to supplement resident instruction and their use was not required.However, a significant number of students who utilized the material indicated that this improved their understanding of the material.In addition, students were asked to indicate whether they would like to complete and submit homework assignments online in the future. The students agreed that they would like the opportunity to complete some, but not all, problems by this method. The concern cited was the inability to receive partial credit.

TABLE II
Survey Results: Usefulness of Online Courseware.

	Agree	Somewhat Agree	Neutral	Somewhat Disagree	Disagree
The online courseware improved my understanding of the class material.	33.3%	33.3%	25%	0%	8.3%
The online courseware improved my class grade.	41.7%	25%	25%	0%	8.3%

IV. Conclusions and Future Work

A library of courseware utilizing Java applets for introductory Microelectronics instruction was developed. Survey results indicate that two out of three students who utilized the material agreed that it helped to improve their understanding of the subject matter and their grade. Future work will concentrate on refining the existing material and developing new applets. For instance, new applets will be implemented to graphically illustrate transistor characteristic curves and show how to utilize them for amplifier design. Audio components will be added to provide applet instructions and to explain concepts. Other methods (e.g. CD-ROM) of distributing the material will be implemented since students report difficulty accessing the material over slower modem connections. There are also difficulties in presentation to be overcome due to different browser versions used and the fact that Java has not fully achieved platform independence.

Acknowledgments

This work was supported by a grant from the Penn State Center for Excellence in Learning and Teaching and the Center for Academic Computing. We would like to acknowledge Carol Dwyer, D. Jay Newman, and Dave Roth for their assistance and thoughtful suggestions.

References

[1] B. Daily and M. Daily, "Effectiveness of a Multimedia Televised Distance Education Program for Engineering Majors," Journal of Engineering Education, vol. 83, no. 4, pp. 383-387, 1994.

[2] J.L. Davis, "Computer-Assisted Distance Learning, Part II: Examination Performance of Students On and Off Campus," Journal of Engineering Education, vol. 85, no. 1, pp. 77-82, 1996.

[3] P. Penfield Jr. and R.C. Larson, "Education via Advanced Technologies," IEEE Transactions on Education, vol. 39, no. 3, pp. 436-443, 1996.

[4] B. Oakley II, "The Virtual Classroom: At the Cutting Edge of Higher Education," IEEE/ASEE Proc. of the Frontiers in Education Conference, Salt Lake City, UT, Nov 1996.

[5] http://www-cm.math.uiuc.edu

[6] http://www.java.sun.com

[7] M. Chirico, F. Giudic, A. Sappia and A.M. Scapolla, "The Real Experiment Execution Approach to Networking Courseware," IEEE Transactions on Education, vol 40, no. 4, 297, 1997.

[8] http://www.blackboard.com/

[9] http://www.ews.uiuc.edu/Mallard

[10] C.R. Wie, "Educational Java Applets in Solid State Material," IEEE Transactions on Education, vol. 40, no. 3, November 1998.

[11] http://www.ece.gatech.edu/academic/computer_education/

[12] J.A. Bragg, C.D. Knight, and S.P. DeWeerth, " Java Programming for Engineers: Developing Courseware for a Computer-Enhanced Curriculum," 1999 ASEE Annual Confernce, Charlotte, NC.

[13] A.S. Sedra and K.C. Smith, Microelectronic Circuit, 4^th Edition, Oxford University Press, New York, 1998.

Author Contact Information

Ralph M. Ford (http://ece.bd.psu.edu/~ford)
The Pennsylvania State University at Erie (http://www.pserie.psu.edu)
School of Engineering and Engineering Technology
Station Road
Erie, PA 16563-1701
Phone: 814/898-6468
Fax: 814/898-6125
E-mail: Ralph-Ford@psu.edu

Jonathan Bondzie
The Pennsylvania State University at Erie (http://www.pserie.psu.edu)
Station Road
Erie, PA 16563
Phone: 814/898-6922
E-mail: Jonathan.Bondzie@compaq.com

Paul Kitcho
The Pennsylvania State University, University Park (http://www.psu.edu)
State College, PA 16801
Phone: 814/861-8597
E-mail: kitcho@psu.edu

Author Biographies

Ralph M. Ford, received the B.S. degree from Clarkson University in 1987, and his M.S. and Ph.D. degrees from the University of Arizona in 1989 and 1994 respectively, all in electrical engineering. He has been a faculty member in the Electrical and Computer Engineering Program at Penn State Erie since 1994 and holds the rank of associate professor. His interests are in the areas of image processing, pattern recognition, computer vision, Java programming, and microelectronics education. He is a member of the Institute of Electrical and Electronics Engineers, the International Society for Optical Engineering, and the American Society of Engineering Educators.

Jonathan Bondzie, received a B.S. degree in Computer Engineering from The Pennsylvania State University at Erie in May 2000. His past projects include modeling Leonard-Jones gases using C++ and Motif under X windows and the modeling microelectronic circuits with Java. His research interests are in artificially intelligent thought processes. He is past-chair and co-founder of the Penn State Erie ACM chapter and a member of the International Who's Who of Information Technology.He currently works as a programmer for Compaq Corporation in Reston, Virginia.

Paul Kitcho, received a B.S. degree in Computer Science from the Pennsylvania State University in December of 1999 with a minor in Engineering Leadership. He was a programmer for Educational Technology Services at the Center for Academic Computing since 1997 and has worked on the development of several web-based programs. He is a member of the Association of Computing Machinery.