The adoption of laminated structure in transformer cores is a key design in electrical engineering, which is underpinned by profound physical principles and engineering considerations.   The challenge of eddy current loss When alternating current passes through the windings of a transformer, a changing magnetic field is generated in the core. According to the law of electromagnetic induction, this changing magnetic field will induce a circular current inside the iron core, which is called "eddy current". If a single iron core is used, these eddy currents will cause a large amount of energy to be lost in the form of heat, not only reducing efficiency but also possibly causing the iron core to overheat.   Solution for laminated structure This design can be made by stacking thin sheets of iron cores and coating each sheet with an insulating layer. 1.Significantly increase the resistance of the eddy current path 2.Limit the flow range of the vortex within a single thin sheet 3.Effectively reduce eddy current loss by over 90% Material and process optimization Modern transformers typically use silicon steel sheets with a thickness of 0.23 to 0.35mm. The addition of silicon further enhances the resistivity. The stacking direction is arranged along the magnetic field lines, which not only ensures the smoothness of the magnetic circuit but also minimizes the eddy current effect to the greatest extent.   This seemingly simple laminated design is actually the best solution to balance efficiency, cost and reliability, and remains one of the core technologies in transformer manufacturing to this day.