Recent Progress in Step-Based Tutoring for Linear Circuit Analysis Courses

Recent progress is described on the development and assessment of a step-based computer-aided tutoring system to teach linear circuit analysis topics. The system automatically generates both AC and DC circuit problems whose topologies and element values are randomly varied, providing an unlimited source of novel problems of any specified difficulty level. Students input each stage of their work in a variety of forms including redrawn circuit diagrams, equations, waveform sketches, matrix equations, numerical answers, and multiple choice answers, and receive immediate feedback on the correctness of their responses. Complete, error-free solutions to the problems are also generated automatically, allowing students to view as many different fully-worked examples as needed. Here, we describe recent developments in the system, including implementation of 13 different tutorials covering topics such as identification of elements in series and parallel, including cases where different “types” of terminals are present; combination of resistors, inductors, and capacitors in series and parallel; and writing and solving both node and mesh equations for both DC and steady-state AC circuits for specified unknown circuit variables. Additional tutorials now in development include sketching the current or voltage as a function of time for an inductor or capacitor, given the opposite such quantity; the mathematical aspects of Laplace transforms; and the sketching of Bode plots from system transfer functions (and vice versa). Additional solution methods are also being developed to support all aspects of DC and AC circuit analysis. We further describe improvements to our tutorial system that now explain wrong answers given when attempting to identify elements in series and parallel, and explain the correct solutions shown in the series/parallel identification, node analysis, and mesh analysis tutorials. Initial results from a laboratory-based study showed a statistically significant 1.21 standard deviation improvement in student performance compared to normal textbook-based homework. The software has been used by over 1290 students at four different universities and some community colleges, with high levels of user satisfaction and generally favorable comments.