Direct-Current RL Circuits with Fixed Resistance and Variable Inductance

• Bogdan M. Leu ^[1]
  1. [1] University of Cincinnati

     University of Cincinnati

     City of Cincinnati, Estados Unidos

     
• Localización: The Physics Teacher, ISSN 0031-921X, Vol. 63, Nº. 3, 2025, págs. 206-208
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Resumen

  • Compared to other circuit elements, inductors and self-inductance seem to find their way less frequently into the lineup of quantitative experiments and demonstrations performed in an introductory physics course. Factors contributing to this situation may include the short timescale of phenomena associated with inductors, the theoretical (calculus-based) background, a lack of suitable, easy-to-use equipment, or simply time constraints.

    The experiment described in this article, requiring a relatively small amount of theory, equipment, and experimental skills, offers a quantitative glimpse into the behavior of inductors in a direct-current circuit and the effect of magnetic cores on the self-inductance. We start with several air-core coils in series, then add cores one at a time. Analysis of the transient response upon closing the circuit as a function of the number of coils with cores yields the self-inductance of the air-core coil and an “effective” magnetic permeability of the magnetic core. Teaching considerations are presented