一般均为叠铁芯，由铁芯叠装而成。卷铁芯的形式较多。渐开线铁芯的心柱与铁轭之间气隙较大，影响空载电流，所以容量不能做的太小；但因漏磁通垂直进入铁芯片平面，影响附加损耗，所以片宽不宜过大，即容量不能太大。
Generally, they are laminated cores and are made up of iron cores. There are many forms of coil core. The air gap between the core of the involute core and the yoke is large, which affects the no-load current, so the capacity can not be too small; but because the leakage flux enters the iron chip plane vertically, affecting the additional loss, the width of the chip should not be too large, that is, the capacity can not be too large.
铁心主要由铁芯本体、紧固件和绝缘件组成：
The core is mainly composed of core body, fasteners and insulation parts.
①铁芯本体、磁导体、由电工钢片制成。
(1) iron core body, magnetic conductor, made of electrical steel sheet.
②紧固件、夹件、螺杆、玻璃绑扎带、刚绑扎带和垫块等。
2. Fasteners, clamps, screws, glass binding belts, rigid binding belts and cushion blocks.
③绝缘件、夹件绝缘、绝缘管和绝缘垫、接地片和垫脚等。
(3) insulation, clip insulation, insulation pipes and insulation pads, grounding plates and pads.