Research in Engineering Education Symposium 2011 - rees2009

Universidad Politécnica de Madrid (UPM) Página 185 de 957
Electrical circuit misconceptions
The understanding of electrical circuits at the level of high school and college has been the
subject of several investigations. Indeed courses seem to focus on the manipulation of
rules and equations in order to solve quantitative problems without developing a coherent
conceptual framework for scientific theories. Courses also seem to introduce students to
solve exercises following procedures, allowing the student to answer correctly even
without having the knowledge of the rules that govern the circuit.
Some of the researches concerning the way in which students acquire knowledge show
that in the learning-teaching process the students come to the classroom with practical
and intuitive knowledge concerning laws and physical phenomenon and that they explain
how things work in the real world based on this type of knowledge.
The research shows conceptual schemes about circuits and electricity (Closset, 1983;
Furió & Guisasola, 1999; Hierrezuelo & Montero, 1988 ; Picciarelli, Di Gennaro, Stella, &
Conte, 1991; Pontes & De Pro, 2001; Shipstone, 1984 ; Varela, Manrique, & Favigres,
1988). This conceptual framework has recollected preconceptions of everyday life
experiences that students take as their own and that are not always correct.
According to those studies, and on what they all agree, the main preconceptions are
(Gonzalez, 2006):
1. Difficulties to distinguish and use terms like: potential difference, voltage, current,
etc.
2. The current is thought as a fluid material.
3. They do not see the necessity for the circuit to be closed for the existence of an
electrical current.
4. They tend to use sequential reasoning. For example, they think that the current
becomes weakened or exhausted as it passes through a circuit or think there can
only be charges after the circuit element changes.
5. They tend to interpret the voltage as a property of the current, instead of
considering the current to be a consequence of the difference in potential between
two points of a conductor.
6. The students have difficulties in interpreting the graphical representations of the
circuits. They are not able of associating the real circuit with their graphical
representations, though it is a question of simple assemblies.
The investigations also showed that when making changes to a circuit students fail to
understand that changes affect all the circuit and have an effect on voltages and currents.
This paper, delve into the so-called local and sequential reasoning described as:
In Local reasoning the students focus their attention upon one point in the circuit. A
change in the circuit is thought on as only affecting the current and/or the voltage in the
point where the change is made (Bernhard & Cartestensen, 2002). In Sequential reasoning
if something is changed in the circuit this is thought on as only affecting current and/or
Proceedings of Research in Engineering Education Symposium 2011
Madrid, 4 th - 7 th October 2011