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This coil, named after its inventor, a physicist from the 19th century, has almost maintained the same appearance since then. The principle is simple: it is a transformer, made up of a core of soft iron wires tightly wound together. The primary circuit consists of a thick wire wrapped around this core. The secondary circuit, made up of a very large number of turns of thin, perfectly insulated wires, is wound around this winding. By creating abrupt interruptions in the primary current, an induction phenomenon is generated in the secondary circuit, resulting in a very high induced voltage. The spark that appears between the rod and the metallic disc above the coil allows the visualisation of the obtained voltage. To see a demonstration, you can watch these videos: [https://www.instagram.com/reels/DOBNE7wCKup/] and [https://www.youtube.com/watch?v=Z5KPojIrNlY].
Bobine de Ruhmkorff (Leybold) Dimensions: L 45 x W 24 x H 33 cm, from the 1980s Kept at the Faculty of Science and Technology of Nancy, Poincaré Building The University of Lorraine is partnering with CNAM and the Greater Nancy Metropolis to lead the PATSTEC (Scientific and Technical Contemporary Heritage) mission at the regional level. More information [here].
Photo: Arnaud Codazzi
