Ring transformers are a major type of electronic transformer, featuring high electrical efficiency, iron cores with no air gaps, stacking coefficients up to 95% or more, minimal leakage flux, low electromagnetic radiation, compact size, lightweight, variable with the core, very low iron loss, and low iron core temperature rise. They are widely used in household appliances and other electronic devices with high technical requirements, primarily serving as power transformers and isolation transformers. Ring transformers have a complete series available internationally and are extensively employed in computers, medical equipment, telecommunications, instruments, and lighting.