EI transformer is one of the electronic transformers, which is defined according to the shape of the core, because the core of the EI transformer is superimposed by the "E" type sheet and the "I" type sheet, so it is called EI transformer. EI transformers are generally power frequency (low frequency) transformers (50HZ or 60HZ), power transformers, and some audio transformers are also EI, such as those used in audio.
