The iron core of a transformer is constructed by using silicon steel plates that are insulated from each other with a layer of varnish. This lamination process is implemented to minimize the occurrence of eddy currents. The core is made up of multiple thin plates of silicon steel that are stacked together, with each plate separated by an insulating layer of varnish. This insulation prevents direct electrical contact between the plates, effectively reducing the formation of eddy currents. Eddy currents are circulating currents that can be induced in conductive materials when exposed to a changing magnetic field. By incorporating insulation between the laminations, the flow of eddy currents is impeded, resulting in lower energy losses and improved efficiency of the transformer. The use of silicon steel further enhances this effect, as it exhibits high electrical resistance, making it an ideal material for reducing eddy current losses in transformer cores.