Some of the major difficulties in this process are that the students have to learn four new computer programs as well as the operation of the PCB mill/drill machine. The first time through, this process is very time consuming because of many potential stumbling blocks-several students completed their PCB only to find out that they had forgotten to mirror their circuit board layout! However, after the initial exposure most students were able to retain enough of the skills, even several months later, that they were able to do the layout/fabrication without major difficulties. Additionally, because we have only one mill/drill machine, it was necessary to start the project during the scheduled laboratory and then allow access and extra time outside lab to finish their projects.

The reward of restructuring these laboratories has been that the students were able to design and fabricate electronic systems on their own printed circuit boards. They began to acquire an appreciation on the overall electronic production process and how that process relates back to design. Additionally, since the students keep their PCB projects they were able to use them in later laboratories as well as for their own experimentation.

Specific educational objectives

There are several levels of learning that take place in these ``production'' PCB electronics laboratory projects. First, the students become familiar with industry-standard software tools for circuit design and issues relating to electronic systems production. The second educational objective is to give the students a unique laboratory experience that substantially adds to their enjoyment of working with electronics while teaching important lessons about electronics production, quality and design.

The third major objective is to overcome the abyss of doubt preventing students from making useful circuits by giving them practice in the full design/build cycle. It is my experience that most electrical engineers lack the ability to transfer their theoretical understanding to actual circuit implementation without additional training. Clearly these are far reaching objectives and cannot be the result of one project. Rather, we see it as the natural culmination of learning in this area starting with an introduction in the Sophomore year, then continued use throughout the Junior year electronics labs and concluding with the Senior year Capstone Design and other class projects.

The approach taken here gives students the opportunity and tools to design and build real-world electronic systems. This is a powerful tool to reshape the way students learn and think about electronics. Hands-on engineering like this is an extremely strong motivational tool and why most of our students are studying to become engineers.

Overview of the Electronics Prototyping Facility (EPF)

There are a number of reasons why this PCB lab project approach is not commonly used. The standard chemical etching method for producing PCBs is well known and it has the advantage of low cost. However, there are a number of serious drawbacks to this method including the time for the etching/drilling process, PCB quality control as well as the storage and disposal of hazardous chemical wastes. Until recently with the development of this PCB mill/drill machine and associated CAD software, the cost, complexity and time of designing/building a printed circuit board has been typically beyond undergraduate laboratories. The key is the vertical integration of all steps so that users can design and construct a system without using outside resources. The CSM Electronics Prototyping Facility consists of the following major components:

• T-Tech's QC-7000 PCB mill/drill/contour route machine

• A 486 computer controller dedicated to the QC-7000

• Several soldering stations, an optical inspection station and misc. tools

• Various software to prepare the Gerber files and control the milling process

• Schematic capture, PCB layout, PLD design and circuit simulation software

Assessment-How well are we doing?

As part of the assessment process, the students were asked to for their anonymous comments about the PCB labs. The student responses to this type of requests are frank and helpful in pinpointing areas of strengths and weaknesses. The overall response was very favorable and the students especially enjoyed the ``hands on'' experience. Areas to be improved upon include better documentation, instruction and reducing the time commitment. The summarized survey results for the 33 replies are shown in Table 2.

My assessment as a faculty member of the introduction of the PCB labs to our Junior year electronics labs is highly positive, but significant work is required to improve the ease of use. Clearly, the documentation requires substantial improvement. The facility also needs a wider range of CAD and hardware tools. Other faculty members will be trained so that they may be able to use the EPF as appropriate. The future looks promising-the key is making this type of laboratory project routine and mainstream throughout the electronics curriculum for both students and faculty.

Conclusions

It is clearly important for electrical engineering students to have practical, hands-on skills including those skills relating to the production of printed circuit boards. In place of three standard build-test-disassemble laboratory projects, our Junior year electronics students designed and constructed several ``electronic systems'' that they keep and use in later projects. These electronic system projects include an adjustable power supply, a variable frequency clock and an adjustable gain linear amplifier. They were selected because they were: appropriate in teaching key concepts in the laboratory; key building blocks for use in later classes as well as for tinkering outside class; and affordable.

The difficulties in this approach are an increase in the time to complete the labs and the students need to learn many new skills the first time through the PCB production process. The advantages are that the students truly enjoy putting their design skills to practical use and they gain industrially relevant electronic experience. These Junior level projects are part of an overall strategy that leads into use of these skills and project hardware in their Senior year. One benefit from this approach is that graduating students will have a far higher level of understanding of the overall design-production cycle and should be more effective as working engineers.

References

1. Hagler, M. ``Hardware Homework for Courses in Circuits and Electronics,'' Proceedings of the 1994 Frontiers in Education Conference, pp. 557-561, 1994.

2. Christiansen, D. ``New Curricula,'' IEEE Spectrum, Vol. 29, No. 7, 1992.

3. Titus, J. ``Where are the Experimenters?,'' Electronic Design News, p. 29, Feb. 1991.

4. Carlson, A. and Schoch, P., ``Electronics Up Front: A Motivational Lab Course,'' Proceedings of the 1994 Frontiers in Education Conference, pp. 72-75, 1994.

5. Strategic Manufacturing Initiative, National Science Foundation, 1992.

6. Adam , J. ``Competing in a Global Economy,'' IEEE Spectrum, Vol. 27, No. 4, April 1990

7. Brown, G., (D-California) Chairman, ``Report of the Task Force on the Health of Research,'' Congressional Records 102nd Session of Congress, July 1992.

8. Feisel, L., Invited speaker, presented at the 1992 Frontiers in Education Conference, November, 1992

9. Conner, D. ``Systems Create Prototype Circuits Boards Fast,'' Electronic Design News, pp. 104-108, July 1992.

10. Herniter, M. ``PC Board Design and Fabrication using Schematics, PADS-PERFORM, and a Laser Printer,'' Proceedings of the 1994 Frontiers in Education Conference, pp. 111-115, Nov. 1994