環かん状じょう鉄てっ心しんMeanings1nountoroidal core; endless coreTechnical term in electrical engineering for a ring-shaped magnetic core used in transformers and inductors.環かん状じょう鉄てっ心しんは変へん圧あつ器きの効こう率りつを高たかめるために使つかわれる。Toroidal cores are used to improve transformer efficiency.