Ring-core transformers are a major type of electronic transformers, featuring high electrical efficiency, iron cores without air gaps, stacking factors as high as over 95%, minimal leakage flux, and low electromagnetic radiation. They have small dimensions and light weight, adapt to the core shape, and exhibit very low iron loss and low core temperature rise. They are widely used in household appliances and other high-tech electronic devices with strict technical requirements, primarily as power transformers and isolation transformers. Ring-core transformers have a complete series available internationally and are extensively used in computers, medical equipment, telecommunications, instruments, and lighting applications.