Abstract:

This year we have started a new approach in our Junior year electronics laboratories. Several laboratory projects were changed to give the students the opportunity to design and build useful circuits that they then can keep and use in follow-on projects. This approach takes advantage of our ``Electronic Prototyping Facility'' which offers a vertical integration of advanced CAD tools with an automated printed circuit board manufacturing system. The students are able to rapidly prototype electronic systems and experience the entire design-production cycle just as they would in industry.

The projects the students constructed include an adjustable power supply, a variable frequency/duty cycle clock and a linear amplifier. The details of this experiment in electronics laboratory instruction along with the promises and drawbacks are discussed.

Introduction-The lack of practical skills

Engineering is defined by Webster's II dictionary as ``The application of scientific principles to practical ends.'' The standard four year engineering bachelor's degree program provides a combination of mathematical skills, scientific training, practical knowledge as well as other preparation. One of the trends in electrical engineering degree programs seems to be a de-emphasis of practical hands-on skill for reasons including: the high cost of running an electronics laboratory in both equipment and faculty time [1]; the advent of excellent computer tools that sometimes are used in place of a hands-on lab; and the students themselves have fewer hands-on skills than previous generations [2].

The need for more practical, hands-on skills has been widely recognized both by industry as well as by the alumni and faculty from electrical programs [1-4]. In particular for electrical engineers, it has been my experience that there is a wide gulf between the design/analysis skills acquired in school and the ability to implement a real electronic system. As a result, students are poorly prepared to enter the work force and deal with the real-world difficulties in implementing electronic circuit designs.

While few electrical engineers will fabricate their own integrated circuits, many will be require to take a circuit from design to prototype or production. With the advent of advanced computer design tools and ``lean'' design teams, engineers in industry can no longer count on an experienced support staff to handle the manufacturing processes. Consequently, many of these engineers must then learn on the job the basic principles of production and manufacture of printed circuit boards (PCBs) with the corresponding lowering of overall efficiency and quality. Thus, I believe it is important for our students to gain a basic knowledge of and develop practical skills for electronic system production.

One of the problems in gaining real world skills is the way schools teach basic electronics laboratories. Typical projects in lower-level undergraduate electronics laboratories focus on teaching key concepts by having the student design, build and test many simple circuits. At the end of each laboratory, the circuit is disassembled. This approach results in a limited opportunity for the student to integrate their previous work into the next project. As a result, students are often frustrated in basic electronics labs as they never quite get to the level where they can design and build anything practical.

Approach-Hands-on electronic systems production

General Concept

The challenge at the Colorado School of Mines has been to dramatically change the way students learn and use electronic circuits by connecting our undergraduate electronics laboratories to our ``Electronic Prototyping Facility'' (EPF). This approach empowers students with the tools and knowledge to apply state-of-the-art techniques in electronic circuit design and construction in the context of their lab work. It also addresses issues important to our educational process in interdisciplinary learning and strongly resonates with major industrial and commercial themes in manufacturing techniques [5], competitiveness and time to market [6]. It is one step in making the education of our students more effective and relevant by focusing on the specific needs of our society in electronic circuit design and manufacturing [7]. This area was highlighted by a recent change in the ABET accreditation requirements for all engineering schools to place greater emphasis on production processes [8].

In the 1994-95 school year we have started this new approach in our Junior year electronics laboratory sequence. Several standard projects were changed to give the student the opportunity to design and build useful circuits that they then keep and use in follow-on laboratory projects. The vertical integration of design software and local/quick/cheap PCB fabrication using the EPF brings an ability to create prototype electronic circuit boards in a matter of hours. This has brought a capability to our undergraduate laboratories to design and construct circuits that used to be abstract problems because the implementation was too difficult or expensive [9]. Students are able to go through rapid prototyping of electronic systems and experience the entire design and production process just as they would in industry. While other universities use the same prototyping equipment for research and at least one other university has also introduced PCB production into electronics labs [10], we know of no other four year degree program using this approach as a major theme for undergraduate electronics laboratories.

Junior-level electronics labs

After an introduction to the CAD tools and printed circuit board production, the students are assigned projects that require the use of this prototyping facility. The projects the students construct over the Junior year are shown on Figure 1.