Interactive www lesson Digital circuits and systems

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1 Interactive www lesson Digital circuits and systems Stuchlíková Ľubica, Gron Michal, Beňo Ján, Helbich Marek, Hulényi Ladislav, Csabay Otto, Redhammer Róbert, Mondočko Peter, Košík Tomáš and Mikulášovič Ján Department of Microelectronics, Faculty of Electrical Engineering and Information Technology, Slovak University of Technology, Ilkovičova 3, Bratislava, Slovakia Abstract The article shows the authors' experience in design and realization Interactive www lesson Digital circuits and systems for course Electronic systems and Electronic devices. This e-learning project is accessible on the free self-educational portal elearn central for the students. This portal uses learning environment MOODLE, which supports international standard SCORM. 1. Introduction Digital circuits exploit the controlled-switch behaviour of electronic devices to process signals which represent numerical or coded data. In most cases these digital signals are binary in nature; that is, they are signals which have only two distinct voltage levels: one near to zero volt and one at a higher level depending on the used supply voltage. These two levels are often represented as L and H. Binary signals are used extensively in communication, control, and instrumentation systems as well as in computers [1]. This topic is one of the significant parts in the courses Electronics and Electronic Devices and Systems. FEI students attend these courses in the second year of their Bachelor study. The benefit of e-learning has inspired us to create an alternative source of information: Interactive www Lesson Digital circuits and systems. This lesson deals with the logic circuits, also referred to as logic gates. The focus is on the operation of the fundamental building blocks which comprise the transistor-transistor logic (TTL), emitter-coupled logic (ECL), NMOS, CMOS and BiCMOS fabrication technologies. This lesson Digital circuits and systems has been supplemented with creating five interactive animations for better projection of study, two types of an interactive self testing module and a glossary. This e-learning project will be a part of the course Electronic Systems and Electronic Devices. This course is accessible on the free self-educational portal elearn central for students and it is located on the server of the Department of Microelectronics FEI STU on the following links and 2. Software We have created the e-learning educational portal elearn central for students (Fig. 1). The current version of elearn central uses a course management system Moodle (Modular Object-Oriented Dynamic Learning Environment) Moodle Why have we decided for Moodle? Moodle [2] is a software package for internet-based courses and web sites production developed in Australia by Martin Dougiamas. It's an ongoing development project designed to support a social constructionists framework of education. Besides, Moodle is an open source software, which means that it is free to download, use, modify and even distribute (under the terms of the GNU General Public Licence [3]). Moodle runs on any computer that can run PHP, and can support many types of databases. The design and development of Moodle is guided by a particular philosophy of learning, a way of thinking that you may see referred to in shorthand as a "social constructionist pedagogy". It is suitable for 100% online classes as well as supplementing face-toface learning. Moodle is available in 45 languages, including Slovak. The software can import course content that is SCORM 1.2 or AICC compliant, and can a export quiz content in IMS QTI 2.0 format. The system includes tools to facilitate the migration of course content between different versions of the software. The chat tool supports images. The system creates archive logs for all chat rooms. Students can view their completed and pending course readings and activities. The software provides three default course templates: activities arranged by a week, activities arranged by a topic, or a discussionfocussed social format. Instructors can create new course or content templates. Instructors can use templates to create discussion forums, links, course content, and resources, and these templates include a WYSIWYG content editor with a spell-checking.

2 to add texts, pictures, animations, etc. to export to a SCORM package for import to Moodle. The generated content using exe can be imported into any Learning Management System as SCORM packages. The exe is being developed in XUL and Python [7] Quizzes The lesson has been supplemented by two types of interactive self testing modules. We created quizzes in the GIFT format for quizzes. The GIFT format proved to be the most comprehensive import format available for importing Moodle quiz questions from a text file. It allows that various question types can be mixed in a single text file, and the format also supports Multiple- Choice, line comments, question names, feedback and percentage-weight grades Authors animation tools Fig. 1. Administration menu elearn Central in Moodle Moodle is a system with real possibilities. For example: Each course can have its own glossary which can be maintained by the instructor or collaboratively by the students. Terms in the glossary that appear in the course can be auto-linked back to the glossary. Thus we tailored Moodle to our needs SCORM package The lesson Digital circuits and systems was converted into a SCORM 1.2 package [4]. SCORM (Shareable Content Object Reference Model) is a model defining relations among the course components, data models and protocols with the aim to make a possibility to interchange these courses among the learning systems satisfying SCORM specification [5]. We used the open Source project exe [6] for converting this lesson from Word Documents to SCORM 1.2 package. The exe project aims to enable teachers to publish web content without the need to be proficient in HTML. The editing of texts and figures is very intuitive and similar to work in Microsoft Office Word editor (Fig. 2 and Fig. 3). The procedure is very simple: to create a new document in exe to create a structure of lesson content Five interactive animations have been developed in Macromedia Flash MX 2004 [8] for this lesson (Fig. 4). We decided to use this authors tools for interactive animation creation because it is able to program this important interaction and it works with scaleable vector graphics. It fulfilled the requirement for the smallest size of animations, vector graphic with the view of nondecreasing quality at higher resolution. An output format of animations can be added to web pages [9]. This programme packet was purchased by the Department of Microelectronics FEI STU for non commercial purposes and the interactive animations created by this software provide interactivity to our lesson besides other benefits. 3. Lesson Content The lesson Digital circuits and systems includes 11 sections, two types of quizzes, both with 10 variations, 5 interactive animations, glossary with 40 terms and number of hypertext references. A single section gives the basic principle definitions and terms connected with digital circuits and systems to FEI students in the second year of their Bachelor study. Section titles are following: A short history Principles of digital circuits Transistor as a BJT inverter Dividing of digital circuits Basic logic circuits Direct-Coupled transistor Logic DCTL Diode transistor logic DTL and Transistor-Transistor logic TTL Emitor-Coupled Logic ECL Unipolar logic circuits NMOS

3 Fig. 2. Open Source project exe working area and toolbars for text editing. Unipolar logic circuits CMOS BiCMOS Digital Integrated Circuits Questions answer after that. He/she may proceed in carrying out the quiz only if his/her answer is correct. This is a very simple way to learn this topic. 4. Lesson quizzes We have designed two types of self testing module - quizzes in Moodle. In both there are available 10 various quizzes with 10 multiple-choice questions supporting single or multiple answers. Results are listed in %. The best results are stored in users account. The user is informed about these results in the case he repeats the test. The first type of quiz is assigned for fast revision of knowledge. The second type of quiz is a learning quiz with a feedback possibility. When a student does not answer correctly, the quiz automatically returns him back to the text related to the question. The student has an opportunity to repeat the 5. Lesson interactive animations We have created five interactive animations using Macromedia Flash MX The conception of these animations is based on a natural human feature gamesomeness. In such a way students can obtain new knowledge by an interesting playful way. The 1st interactive animation is a transistor as BJT inverter. It enables to a student to understand relation between a function of a transistor in a circuit with a common emitor and transfer characteristics and output VA- characteristics. The 2nd animation is intended for a simulation of a logic gates function. The students can combine different types of logic gates and to follow an output

4 Fig. 3. Open Source project exe working area and toolbars for text and pictures editing. logic level. The 3rd interactive animation is about the principle of of logic TTL NAND gate operations. It shows the circuit scheme of a TTL NAND and its function after choosing logic levels on inputs (Fig. 5). The 4th animation is about a physical principle of CMOS invertor. It shows an effect of a changing input voltage. Students can see the change in inner CMOS structures in very simple models (Fig. 6). The 5th animation shows the basic function of logic NOR, NOT, AND gates made by the CMOS technology (Fig. 7). All of these animations have the goal to improve understanding of logic circuits and systems. Once again we need to define new templates for floating current, voltage changes and other characteristics (Fig. 6). All animations are added into the education text (they are part of SCORM package) and also into the animation section. There is a link to ask users with the following questions under all animations. Do you have any previous experiences with e-learning? Does this method of study suit you? Is this kind of study technically accessible for you? Is the above animation sufficiently understandable for you? Is the above animation interactive enough? Did this animation help you to understand the substance of the described phenomenon? The feedback can help us to improve our work. 6. Glossary Moodle has a possibility to create a glossary which can be maintained by the instructor or collaboratively by the students. Terms in the glossary that appear in the course

5 can be auto-linked back to the glossary. We decided to use of this ability of Moodle modul Glossary. We are creating our own glossary. Now the glossary has more than 40 explanations. Our goal is to prepare glossary with all terms used in our education text. One of the ways to realize exhaustive own glossary in Moodle (the system supports the creation of Wikis) is to use model of WIKIPEDIA and assistance of our users - students. But our idea will be evaluate after longer time. Fig. 6. A a physical principle of CMOS invertor. Fig. 4. Macromedia Flash MX 2004 Proffesional working area Fig. 7. The basic function of logic NOR, NOT, AND gates made by the CMOS technology 7. Lesson creators Fig. 5. Logic TTL NAND gate 7400 This lesson was created by cooperation of all authors of this paper. It is results of team project Digital electronics systems for student of 2 nd Bachelor study year as an alternative source of education e-learning and bachelor a project Unipolar logic circuits CMOS We have been communicating together on regular basis, either in face-to-face meetings, by or by using of the new created course Team project on educational portal elearn central. We tried to use the electronic support for our work from system Moodle. Each consultation was based on teacher-student interaction with equal rights.

6 8. Conclusion We created the new interactive lesson Digital circuits and systems for the course Electronic systems and Electronic devices. This e-learning project is accessible on the free selfeducational portal elearn central for the students. There is a free access to this lesson and all our portal elearn central not only for students but for all if they are interested. We defined new template of colours for floating current circuits scheme, to wide library of symbols for our courses. The principle of standards, then the basic effects and symbols we introduced before this lesson. These principles showed as the best way for the better understanding and intuitively controlling of animations. This lesson was created by cooperation of students and teachers. A new course Team project was created and located on educational portal elearn central. It was one of communication tools between members of the team (without mail, SMS, team meetings) and at the same time it was a free source for all of students team members and teachers of actual materials and preliminary versions of animations, a test version of glossary, a test of converting text of equations. According to our experience, we think that a cooperation teachers with students is one of the most prospective ways in support of e-learning materials design. 10. References [1] Millman, J., Grabel, A., Microeletronicsn, McGRAW-HILL BOOK COMPANY, Singapore, 1987, ISBN X. [2] Moodle, 2005, [3] GNU Operating System - Free Software Foundation, 2004, [4] Reusable elearning Object Authorng &Delivary, 2005, Reload Editor v1.3 (SCORM) [5] SCORM, Advanced distributed learning [6] exelearning authoring, 2005, [7] Developer info The exe project, 2005, [8] Macromedia Inc., 2005, Macromedia Flash, Product Overview, [9] Gron, M. and Stuchlíková, Ľ.: Interactive www guide for practice laboratory exercises of subjects Electronic systems and Electronic devices, In: 5th International Conference Virtual University. Proceedings. Bratislava, December 16-17, 2004, pp , ISBN Acknowledgment This work was partially supported by project KEGA 3/0053/02.