Ring transformers are a major type of electronic transformers, featuring high electrical efficiency, iron cores without air gaps, and a stacking factor of up to 95% or more. They have minimal leakage flux and electromagnetic radiation, small dimensions, and light weight. Their size varies with the core, with very low iron losses and low core temperature rise. They are widely used in household appliances and other high-technical-requirement electronic devices, primarily serving as power transformers and isolation transformers. Ring transformers have a complete series available internationally and are extensively used in computers, medical equipment, telecommunications, instruments, and lighting.