Inductive-resistive circuits with constant current: analysis of its treatment in University Basic Level textbooks

Abstract

This study is formulated from the recognition of certain difficulties that University students experience in learning time-dependent electromagnetic phenomena. It describes, through content analysis of twelve-frequently used College textbooks in Argentina, the perspective from which electrical circuits formed by inductor, resistor and constant current source connected in series are approached. We found out that in most texts, the circuit is implicitly modeled as an isolated system, and the descriptive equations of the phenomena associated with the processes of current increase and decrease are deduced from the principle of energy conservation. In addition to the predominance of the mathematical instrumentalism of the subject, temporary equations, which are not plotted, and graphs whose equations are not explicit are presented, making reading comprehension difficult for students. The images, analogies, historical references and applications to everyday life are scarce. We conclude that learning transient phenomena in circuits of this nature, using as the main reference textbooks, can be an arduous task. These resources would encourage, in a limited manner, the building of mental models in accordance with the scientific ones.