group of various transformers with coils and black core on white background

background black blue circuit closeup coil component conductor copper core design detail development device different disposal eco ecology electric electrical electricity electromagnetic electronic electrotechnology element energy engineering epoxy equipment ewaste ferrite ferromagnetic field group inductance induction inductor industrial industry isolated macro magnetic material mounting network nobody nopeople part passive plastic recycling red repair replace research resin science service set shop single spare store supply technical technology transfer transformer voltage waste white whole winding wire