Black Friday: lifetime access is on a special offer in the app, until November 30. Black Friday: special offer on lifetime access, until November 30. Download
계전기는 전기 회로에서 신호를 전달하는 데 사용됩니다.Gyejeongi-neun jeongi hoeroeseo sinho-reul jeondalhaneun de sayongdoemnida.A relay is used to transmit signals in an electrical circuit.