I-EFD transformer core ihlanganisa kokubili ukucaba okwedlulele okunamandla aphezulu kakhulu okukhipha amandla kumafrikhwensi afika ku-1MHz nangaphezulu. Yonke i-transformer, esekelwe ebangeni le-EFD, inobude besakhiwo obuphansi kunanoma yimuphi omunye umklamo okhona wephrofayili ophansi onevolumu efanayo kazibuthe.