Transformer is a static electrical device that transfers energy between circuits through electromagnetic induction, featuring voltage conversion, electrical isolation, and high transmission efficiency. Its core is typically made of silicon steel sheets (for power transformers) or ferrite/nanocrystalline alloys (for high-frequency applications), with windings using copper or aluminum conductors and insulation materials like kraft paper or epoxy resin. Transformers are widely used in power grids (for voltage regulation), industrial equipment (such as rectifiers and welding machines), electronic devices (power adapters), and renewable energy systems (wind/solar power conversion), playing a critical role in electricity transmission, distribution, and utilization across various voltage levels.