Research in Engineering Education Symposium 2011 - rees2009

Universidad Politécnica de Madrid (UPM) Página 43 de 957
Proceedings of the conference
1º Session – Wednesday morning
Topic: Threshold Issues – Chair: Maura Borrego
Investigating and addressing student difficulties in introductory electrical
engineering
Christian Kautz
kautz@tu-harburg.de
Hamburg University of Technology
German
Abstract: We briefly review some previously published results and present some
original data on student understanding in introductory electrical engineering
courses. These results indicate that many students do not understand or do not
appreciate the model nature of circuit analysis in electrical engineering.
Moreover, this lack of understanding or appreciation may affect their
performance on standard tasks in circuit analysis, especially those that require a
functional understanding of electric potential.
Introduction
At a recent conference, we described an approach to improving instruction in introductory
electrical engineering courses that is based on an empirical investigation of student
understanding of selected topics (Kautz, 2011). There we presented data on student
difficulties with determining phase relationships in AC circuits and gave a description of
our instructional materials that appear to help strengthen student understanding of this
topic. We observed that students’ incorrect interpretation of the characteristic phase
behavior of resistive, inductive, and capacitive elements led them to statements that
contradicted a straightforward application of Kirchhoff’s current and voltage laws. From
the data, we concluded that the students’ understanding of these circuit laws was often not
sufficiently robust to withstand the confounding effect of their difficulties with AC phases.
In our paper, we referred to the theory of threshold concepts as proposed by Meyer and
Land (2003) and briefly explored the idea that the existence of two such threshold
concepts may account for our observations.
The first of these we conjectured to be electric potential. By failing to recognize electric
potential as a property of nodes (or points) in a circuit, some students are unable to
identify quantities of common phase among a circuit’s voltages and currents with various
phase relationships. At the level of a metaconcept of circuit analysis, we proposed to
consider the model itself as a threshold concept. Student failure to interpret circuit
diagrams as a graphical representation of a set of mathematical equations may, for
Proceedings of Research in Engineering Education Symposium 2011
Madrid, 4 th - 7 th October 2011