铁芯中套绕组的部分称为“心柱”，不套绕组只起磁路作用的部分称为“铁轭”。凡铁芯包围了绕组就称为壳式；凡绕组包围心柱的称为芯式。壳式和芯式各有特色，但是由铁芯就够所决定的变压器制造工艺却大有区别，一旦选用了某种结构就很难转而产生一种结构。我国大多变压器铁芯采用叠积芯式。
The part of the winding in the core is called the "core pillar", and the part of the winding that only acts as the magnetic circuit is called the "yoke". Where the iron core surrounds the winding, it is called shell type; whereas the winding surrounds the core column, it is called core type. Shell type and core type have their own characteristics, but the manufacturing technology of transformer determined by iron core is quite different. Once a certain structure is selected, it is difficult to produce a structure. Most transformer cores in our country adopt stacked cores.