Ring transformers are a major type of electronic transformer, featuring high electrical efficiency, a solid iron core with no air gap, a stacking factor of up to 95% or more, minimal leakage flux, and low electromagnetic radiation. They are compact in size, lightweight, variable with the core, have very low iron loss, and a 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.