A Teaching Laboratory in Analog Electronics

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456 IEEE TRANSACTIONS ON EDUCATION, VOL. 51, NO. 4, NOVEMBER 2008

A Teaching Laboratory in Analog Electronics:Changes to Address the Bologna Requirements

Rafael Magdalena, Antonio J. Serrano, Jose D. Martn-Guerrero, Alfredo Rosado, and Marcelino Martinez

AbstractTraining new electronics engineers presents severalmajor challenges. This paper proposes a new approach for prac-tical lessons in second-level analog electronics, where students geta closer view of real-world practices in electronic engineering. Theauthors describe and evaluate a more dynamic way of teachingpractical lessons in analog electronics in the first year of anelectronic engineering degree. The method consists of creating avirtual company that contracts students to develop prototypes.The design process involves theoretical concepts from the studentslessons, and poses challenges with respect to costs and teamwork.The method brings the students closer to the working environmentof electronic engineering, and also reinforces both the studentsresponsibility and their interest in practical matters in electronics.

Index TermsAnalog electronics teaching, cooperative work,teamwork, workgroup teaching.

I. BACKGROUND

THE European panorama of university studies has evolved

quickly in recent years. The approach of creating a

common European university space is changing the various

national points of view with regard to teaching university-level

education. The Bologna meeting of 1999 set the convergence

of all the national university programs of the European partners

on a path towards a common frame [1], [2].

The main recommendations of this meeting can be summa-rized as follows: new equivalent degrees should come into being

across the European Union (EU), on more specific subjects or

areas, and of shorter duration. During these degrees, a more

practical approach to teaching is desirable, an aspect which be-

comes more important in technological degrees, where within

a short time students will graduate and search for jobs in fast-

evolving companies. Usually, the duration of such degrees is

about two or three years. In order to define a common frame-

work for comparing the same studies within the EU, the Euro-

pean Credit Transfer System (ECTS) has arisen. This system

measures the work burden of a subject in terms of time, setting

the measurement unit as the work a student can do in one hour.In recent years, university degrees in Spain have been

evolving towards these EU recommendations. The most signifi-

cant changes are the new programs for Bachelors and Masters

degrees, new doctoral programs, and a new legal structure for

the functioning of universities [Ley de Ordenacin de las Uni-

versidades (LOU)] [3]. The Spanish universities are preparing

Manuscript received June 23, 2005; revised November 10, 2007. Current ver-sion published November 5, 2008.

The authors are with the University of Valencia, 46010 Valencia, Spain(e-mail: [email protected]).

Color versions of one or more of the figures in this paper are available onlineat http://ieeexplore.ieee.org.

Digital Object Identifier 10.1109/TE.2007.912553

the necessary changes to meet the ECTS requirements in 2009.

One of the main aspects that Spanish universities take into

account is related to teaching methodologies. New degrees will

pay more attention to practical issues in the various subjects,

will lean towards problem-based learning, and will feature a

closer monitoring of the work of the students by the teacher,

characteristics that are less common in existing degree pro-

grams.

II. CURRENTMETHOD

A. Electronic Engineering at the University of Valencia

The proposed method of laboratory teaching was tested inthe electronic engineering degree program. Due to the partic-ular characteristics of this degree, most of the students are veryyoung, with little or no previous knowledge of electronics. Thelack of background means that competent technical engineersmust be trained in three years, starting from zero. This fact im-plies a major challenge that comprises not only that of impartingtechnical knowledge, but also of mastering the psychologicalskills required to motivate and teach crowded classrooms ofyoung people [4], [5].

The usual structure of every module is based on lectures,

where theoretical concepts are explained and illustrated usingcalculated examples, and laboratory lessons where practical cir-cuits, based on theory lessons, are implemented. The studentsusually carry out these laboratory lessons either individually orin groups of two. The latter is the most common choice. Thisstructure is quite common in an electronics degree, but suf-fers from some major disadvantages. First, guided exercises andpractical sessions often promote a passive attitude in the stu-dent, who may make an effort to fill the spaces in the practicalnotebook, being uncritical of the work done. The result is that,frequently, the student carries out the required task, but does notunderstand the electronic concepts that underlie the work. An-other issue is that parasitism is possible under this policy. One

of the students in the pair can do all the work, while the otherbenefits by receiving the same mark, without having done anywork at all. The questions posed to students regarding importantaspects of the work try to eliminate this aspect, but such ques-tions are only given a subjective mark and crowded labs reducethe effectiveness of this method. A further drawback is that mostof the time, practical sessions do not investigate a practical cir-cuit but merely work as an example of theoretical concepts, sothere is not much additional teaching in these practical lectures.The current system is just a repetitive structure, a mechanicaltask where the components are changed from one form to an-other, but which bears no relation to the industrial setting. Inaddition, this policy promotes neither competitiveness amongst

students, nor collaborative work, nor the ability to assign tasks

0018-9359/$25.00 2008 IEEE


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MAGDALENA et al.: TEACHING LABORATORY IN ANALOG ELECTRONICS 457

and duties in a project. Therefore, a new policy for practical

work, and an appropriate suite of lessons, had to be designed to

overcome these drawbacks [6][8].

III. PROPOSED METHOD

Usually, jobs in electronic-related companies require thepreviously mentioned skills: collaborative work, team and

task management, and an aptitude for concept synthesis and

decision-making. Other aspects are also critical in industrial

environments: cost, performance, size, power consumption,

etc. All of these considerations prompted the authors to devise

a new environment for practical lessons in Analog Electronics

II, a second-year course, which conveyed all of these job-re-

lated skills [4], [9], [10]. The main objectives were to provide

high-quality teaching to students, both in terms of content

and presentation, in order to motivate students and achieve

effective collaboration from them in the classroom, and to teach

additional skills not directly related to electronics (practical,

teamwork, prototype cost, etc.), considered as very valuable in

the professional working environment [9][11].

Aalborg University, Aalborg, Denmark, has a long tradi-

tion in the development of modern, unconventional teaching

programs. For example, over the last 25 years it has been

running problem-oriented, project-organized undergraduate

education [12]. One of Aalborg Universitys trademarks is

its unique pedagogic model of teaching: the problem-based,

project-organized model (problem-based learning). In this

method, a great part of the semesters teaching and student

work revolve around complex real-life problems or issues that

the students consider and try to resolve scientifically while

working together in groups. Half of each semester is devotedto a project and the remaining half to courses [12], [13]. Each

group, typically consisting of six students, has their own group

room equipped with computer terminals, which serves as their

base from 8 a.m. to 4 p.m. every day. The learning theory is so-

cial constructivist and based on Cowans ideas about reflection

in the learning process [14].

In the work presented here, students have to decide at the

beginning of the term between the old or the new method for

their laboratory lessons. If the new method is chosen, the student

must continue attending theory lessons in the classroom, but

s/he must not attend the formal laboratory sessions. Instead, s/he

is given free access to lab facilities in order to design, build andtest the prototype.

The lecturer acts as a contractor. He asks the students (acting

as subcontractors) to design and implement a fully functional

device that covers all the topics reviewed in the theory lessons

(amplifiers, filters, comparators, clippers, clampers, rectifiers

and oscillators, as well as other electronic circuits covered

in earlier modules). The first classes are spent creating a

step-by-step design of thefinal product: the specifications and

main functions are described, and a functional block diagram

(phrased in general terms, not in electronic concepts as yet)

is conceived. This block diagram is reviewed systematically

during the term, whenever an electronic circuit or system fits

any block of the diagram. This policy means that studentsfind

the explanation of circuits and ideas to be useful because they

Fig. 1. Requisition form for components.

can see a direct application. In addition, the start-to-finish de-

sign, from block diagram untilfinal implemented circuit, helps

students in the task of determining, solving and grasping prob-

lems. Another benefit is that the students must pay particular

attention in class in order to complete the proposed prototype.

In thissimulated company,the lecturer also acts as a con-

sultant, when students need to solve any practical or design

problem related to the device. The time spent by the lecturer

on solving problems or helping students to make the prototypework is noted; later, when the prototype cost is evaluated, this

help is converted tovirtual moneyand added to thefinal cost.

This method penalizes students who rely excessively on the lec-

turer to solve problems, and benefits those who try tofind solu-

tions by themselves. On the other hand, if students rely totally on

themselves for the design, incorrect designs or methods might

only be discovered at the end of the term. Therefore, an auditing

task is also undertaken by the lecturer. During six sessions of

2.5 hours, the lecturer reviews the designs and circuits, and ad-

vises the students as to possible errors or mistakes. Therefore,

the lecturer is responsible for ensuring that each groups design

is correct and that thefinal prototype is a working unit.

Finally, the lecturer also acts as vendor. Every component

needed is ordered from the lecturer. Fig. 1 shows a component


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Fig. 2. Scalable prototype boards.

requisition form (translated into English). Educational labora-

tories have a reasonably good stock of the most common and

popular components required for practical lessons, so this is a

good reference for the students. The electronics lecturer always

provides a list of available components and their prices at the

beginning of the term. For an objective treatment of resources,

these prices are drawn from common, independent component

distributors (in 2006 the price list from Farnell was used) [15]. If

the students need an exceptional component, not available in the

repository, the lecturer, acting as contractor, has the authority to

authorize or deny the purchase of this component, on the basis

of the studentsreasoning. If the purchase is approved, the price

is increased from the official price list by 50%, in considera-tion of shipping costs, prices for small quantities and so on, and

a warning is given of the time penalty that may be incurred if

shipment is delayed, to ensure that students take these draw-

backs into account.

At all times, the students have free access to standard data

sheets, application books and computers with Internet access,

and they are encouraged to use them in order to find the compo-

nents or circuits best suited to the design. As previously men-

tioned, the laboratory sessions act as control sessions for the

design.

The final prototype is usually implemented on prototype

boards, which can be easily expanded, so the blocks are assem-bled on several boards and interconnected in the final stages,

as can be seen in Fig. 2. If the students wish, a printed board

is also built (mainly to give them encouragement, and with no

additional cost for thefinal prototype).

During 2005 the recommended size of the student working

group was three people, although several groups of two or four

people were allowed in exceptional cases. Each work group had

to nominate a project manager who was responsible for the de-

sign and task management. Task assignment is a critical aspect

in this kind of practice [16]. Experience has proven that, most

of the time, when students work in pairs, one carries out all the

work. This problem may increase when work groups increase

in size. In order to avoid this problem, the lecturer comments

on the importance of sharing tasks during the development of

Fig. 3. Block diagram of the R detector.

the project. At the end of the term, each group must defend the

design and its implementation in a public session. The lecturer

may question any team member, or may change the speaker, in

order to measure the degree of integration of every student in the

group. Additionally, each group presents a report where task as-

signment is described, and schematics, design notes, and every

important design aspect are detailed.

A students mark for this practical part is decided based on

the cost of the prototype (including material and consulting ser-

vices, 25% of the mark awarded), specifications achieved (40%

of the mark awarded), final report (20% of the mark awarded)

and public presentation (15% of the mark awarded). This prac-

tical mark counts towards 25% of the students total mark, withthe other 75% being for the traditional theory test that every stu-

dent takes at the end of the semester.

IV. RESULTS

In 2006, the second year in which this pedagogic method was

implemented, the proposed prototype was an acoustical output

QRS detector, as can be found in [17]. The system accepts an

input of an amplified standard electrocardiogram (ECG) (1Vpp

from a Dinatech ECG simulator), and must process the signal

to detect the R peak of the signal and give a visual and audio

output when the R signal is detected. If no peaks are detected

within a predetermined time (10 seconds), a different and loudaudio alarm must be fired. The block diagram of the system,

shown in Fig. 3, comprisesfilters, pulse electronic systems, os-

cillators, and power audio amplifiers, which are the main elec-

tronic blocks in the module. Additional design aspects (such as

low power consumption, accuracy, low battery signals, etc.) can

be observed by students, but lie outside the scope of the module.

Nevertheless, students are encouraged to be aware of these as-

pects.

The system was implemented for the second time during

2006, and has meant a major change in the classical concept

of practical lessons in this engineering degree. Students have

shown a great deal of interest in this method, compared with

the usual laboratory lessons, probably due to the innovative

approach and the freedom allowed by the system. Nevertheless,


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MAGDALENA et al.: TEACHING LABORATORY IN ANALOG ELECTRONICS 459

some crucial drawbacks were detected, all of which were

predicted to a greater or lesser extent. One problem was the

considerable freedom conferred on students, which often means

that they embark upon the design carelessly, usually at the end

of term. Since the natural burden of work for students increases

at this time, students may decide to postpone some modules

for the following year or dedicate more time to other subjects,so the initial motivation fades out along the semester. Despite

being expected, this issue was nevertheless quite hard to solve.

During the term, the lecturer tried to drive the work of the

students to ensure that most of the work was completed by

the end of term. The difficulty with this was that some of the

necessary circuits are only explained in the final stages of the

course. Another direct consequence of this drawback was that

some students abandoned the design project, with the result that

the design teams became weak and in some cases two teams

had to be merged in order to finish the prototype. Although

some changes in teams are common in the industrial world,

the excessive number of students withdrawing from the project

complicated the task of development for other students. Another

issue detected in 2006, but one that could be controlled, was

the problem of detecting the true amount of work carried out

by each team member, and to detect noncollaborative students

within a team. As previously indicated, the lecturer dealt with

this by randomly asking the team members questions during

a public presentation of the project. Additionally, the team

manager is responsible for task and member management, so

this kind of training has been revealed as beneficial.

A survey wasfilled in by the students when the project was

finished. The answers were used to improve the following years

methodology. The survey consisted offive questions about the

new practical method and a free text field. Table I shows thetranslation of the 2005 survey.

In 2005, 43 surveys were taken. The results can be seen in

Fig. 4. All responses had high values, so it can be inferred that

students consider the proposed method as valuable for their ed-

ucation. With respect to Questions 1 and 5, most of the students

consider the approach more useful than the classical one, and

would recommend it to other subjects. Questions 2 and 4 are

centred on a value of 4, so students consider that the method

improves their learning and skills in electronics. Nevertheless,

the high values in Question 3 reflect that students feel that the

burden of work has increased. The authors estimate that student

time in the laboratory increased by 50%.During the period 20052006, 57 students out of a total of

268 in the module finished the final prototype; 31 students aban-

doned the initial project. Students who did not pass the prototype

design had to pass a practical test in order to pass the subject.

Official surveys by the University of Valencia, Valencia,

Spain, were also examined in order to assess the impact of

the new methods in students opinion. These official surveys

contain 14 questions about theoretical lessons and another 14

for practical lessons. There are three specific questions about

material and methods in both surveys (Table II). It is valuable

to note that the results of the surveys have improved in this area

during the 20052006 period. It should be taken into account

that during 2006, only 43 students applied to follow the newmethod (approximately 30%), so their influence on the survey

TABLE I

QUESTIONS ON THE 2005 SURVEY

Fig. 4. Responses to the survey questions of Table I.

was small. Nevertheless, results improved, mainly in 2006, and

this change could reflect the new approach towards practicallessons.


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TABLE II

RESULTS OF THE OFFICIALUV SURVEYS INPERIOD20012005

V. IMPROVEMENTS FORFUTUREYEARS

Future implementations of the project will incorporate new

ideas to increase student retention. The size of the teams will

be constrained at three, or very exceptionally, four students. At

the beginning of the module, the system will be explained to the

students and they will have about one month to decide if they

wish to embark on the design. Students with no interest or avail-

ability for the project (approximately 5% of students are actuallyworking, and most of them can not attend lessons) will have to

passa practical test at the end of the term and they can attend the

laboratory for voluntary practical sessions. Students who em-

bark on projects will not have to pass the aforementioned prac-

tical test. Giving up the project will mean that they will have to

pass another closely related practical test. Teams finishing the

prototype will be considered as test passed with honourable

mention.

VI. CONCLUSION

The system presented here has been evaluated as quite in-

teresting and valuable for students. This approach avoids arti-

ficial practical work and proposes a more real-life approach toproblems, taking into account factors such as cost of develop-

ment, collaborative work, consulting issues, team management,

task distribution, etc. The presented practical approach brings

the activities in the university closer to the industrial world. The

system also impels students to develop more responsible atti-

tudes, learning to solve problems by themselves without the pro-

tective cloak of the lecturer. Moreover, it is a good starting point

for students to become acquainted with project development, a

compulsory module in the third year of the degree. The expe-

rience has been very productive and useful, and authors expect

to expand the system to other modules in the degree that are

closely related to hardware electronics.REFERENCES

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Rafael Magdalenareceived the M.S. and the Ph.D. degrees in physics from theUniversity of Valencia, Valencia, Spain, in 1991 and 2000, respectively.

He has been a Labour Lecturer of electronic engineering with the Univer-sity of Valencia for the last ten years. Previously, he was a Lecturer with thePolitechnic University of Valencia and a Funded Researcher with the ResearchAssociationin Optics. He has held industrial positions with several Spanish elec-tromedicine and information technology companies. He has conducted researchand authored works in biomedical engineering and telemedicine. Currently, heteaches courses in analog and digital electronic design.

Antonio J. Serrano received theB.S. andM.S. degrees in physics andthe Ph.D.

degree in electronics engineering from the University of Valencia, Valencia,Spain, in 1996, 1998, and 2002, respectively.He is currently an Associate Professor in the Electronics Engineering De-

partment, University of Valencia. His research interest is in machine learningmethods for biomedical signal processing. Currently, he teaches courses in

analog electronic design and digital signal processing.

Jose D. Martn-Guerrero received the B.S. degree in physics and the B.S.,M.S., and Ph.D. degrees in electronics engineering from the University of Va-lencia, Valencia, Spain, in 1997, 1999, 2001, and 2004, respectively.

He is currently an Assistant Professor in the Department of Electronic Engi-neering, University of Valencia. His teaching is focused on basic analog elec-tronics. His research interests include soft-computing and its application to dif-ferentfields, such as medicine, image processing, marketing, and Web mining.

Dr. Martn-Guerrero is a member of the European Neural Network Society.

Alfredo Rosadoreceived the B.S. and Ph.D. degrees in physics from the Uni-versity of Valencia, Valencia, Spain, in 1993 and 2000, respectively.

He is currently a Lecturer and Researcher in the Department of ElectronicEngineering, University of Valencia. His work is related to automation systemsand digital hardware design in severalfields.

Marcelino Martinezreceived the B.S. and Ph.D. degrees in physics from theUniversity of Valencia, Valencia, Spain, in 1992 and 2000, respectively.

He is an Associate Professor in the Digital Signal Processing Group, Depart-ment of Electronics Engineering, University of Valencia, where he has beenemployed since 1994. He has worked on several industrial projects with privatecompanies (in the areas such as industrial control, real-time signal processing,and digital control) and with public funds (in the areas of foetal electrocar-diography and ventricularfibrillation). His research interests include real- timesignal processing, digital control using DSP, and biomedical signal processing,

with special interest in developing real-time algorithms for noninvasive foetalelectrocardiogram extraction.

A Teaching Laboratory in Analog Electronics

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