This paper presents the introduction of problem-based learning (PBL) in a power electronics course at the University of Oviedo, Gijon, Spain, by means of two practical projects: the design and construction of a switching-mode power supply (SMPS) prototype and the static study of a dc-dc converter topology. The goal of this innovation was for students to apply in practice the knowledge they had acquired in theory classes. PBL is known to be a motivating, problem-centered teaching method that brings the real professional world closer to the student. The instructors thus considered PBL to be the most suitable methodology to obtain the desired results. The underlying methodology, task planning, and assessment of these projects will be presented. Furthermore, the influence of the introduction of PBL in practical sessions versus the traditional teaching method will be discussed. Finally, the instructors' reflections and conclusions regarding the application of PBL in this course from 2007-2009 will be presented. (Contains 1 table and 5 figures.)