As part of a new effort to investigate the learning and teaching of concepts in thermodynamics and electronics that are integral to both undergraduate physics and engineering programs, we have been examining student learning in electrical engineering and physics courses on circuits and electronics. Due to the considerable overlap in the content coverage, we have been able to administer the same (or similar) questions to students in both disciplines. A major goal of this work is to investigate the impact of disciplinary context on the nature of student understanding, including the prevalence of specific difficulties. This paper focuses on foundational concepts of circuit loading that are critical to the design and analysis of circuits covered in both courses investigated. In this preliminary investigation, we find that between one-quarter and one-third of students in both disciplines still struggle with basic concepts of voltage division and loading after electronics instruction.