Abstract:

This work presents a teaching experience developed at the grade level on Sound and Image Engineering. Students face their first contact with the Electronics Laboratory on the second semester of the grade. Although they use to fulfill the theoretical aspects of this matter, they also use to encounter difficulties to bring their knowledge to the real world, i.e., to fulfill their laboratory tasks.

The main problem is that, at this introductory level, students still focus on replicating a priori known results, rather than understanding the experimental setup. This behavior affects the way they understand simple electronics concepts, leading to mistakes and misinterpretations on further (and more complex) laboratory sessions.

Breaking this dynamic is a necessary teaching initiative to provide the students with basic laboratory skills. The usual approach is the proposal of some test circuits of increasing complexity for the students to put them together with standard electronic components, and check their behavior by gathering a series of typical measurements. As the setup is highly predictable, students soon fall into looking for a priori known results, sometimes without even thinking about what they are doing. Thus, they need to be continuously reminded that a measurement without its interpretation has no learning value.

We propose an alternative method to achieve the goal of breaking the aforementioned dynamic. The first laboratory task we present to our students consists on building their first basic RC circuits from self-made components, instead of using standard commercial electronic components. Students are guided to build surface resistors by painting graphite rectangles of different sizes with a soft pencil on a sheet of paper. In order to build capacitors, the paper is used as dielectric and the plates are graphite layers colored on both paper sides.

With such self-made components, students are told to fulfill some basic tasks, as characterizing components, proving basic electronics laws, and testing capacitor charge and discharge process. This way, they can get a feeling of the experimental variability and are invited to make deductions about different factors that might affect their results.

The laboratory tasks are presented as research and discovery problems. Every student achieves slightly different results: there aren´t any ideal measured values to achieve and there is no point on trying to mimic the teacher’s or some other student’s results. Thus, everyone needs to think about his/her own results, understand them and decide if they make sense according to the electronic principles.

As a further help, a collection of short demonstrative video-clips, one per task, has been previously recorded. Each video is projected in loop-mode on the classroom screen while students are working. At any time during each session, students can watch the demonstration and relate it with their own implementation. Nevertheless, they still need to understand their own measurements.

As a result of the experience, students reported to feeling highly motivated to fulfill the proposed tasks. Furthermore, we have observed a positive change in the students’ attitude, towards a thoughtful, attentive development of the laboratory tasks. We look forward to comparing final semester evaluation from this group to that from former years.

Keywords:

Active learning, learning by doing, electronics.