结构特点上，O型铁芯就是由一条曲线硅钢片卷绕而成的截面为圆形或椭圆形的环形铁芯，为顺磁路环形结构，磁路完全闭合，无漏磁，磁性能极优；还可以根据截面形状分为截面圆形的OA型铁芯和截面椭圆形的OB型铁芯。
Structurally, O-core is a circular or elliptical core with circular or elliptical cross-section, which is made of a curved silicon steel sheet. It is a paramagnetic ring structure. The magnetic circuit is completely closed, without magnetic leakage and has excellent magnetic properties. It can also be divided into OA-core with circular cross-section and OB-core with elliptical cross-section according to the cross-section shape.
O型铁芯兼具R型铁芯和环形铁芯的优点，因此性能极优，加上价格比R型便宜，又有可定制规格的优势，性价比极高，可用于HIFI音响、精密仪器、400Hz变压器和互感器、电抗器等电磁元件中。
The O-core has the advantages of both R-core and ring-core, so it has excellent performance, low price and customizable specifications. It can be used in HIFI audio, precision instrument, 400Hz transformer and transformer, reactor and other electromagnetic components.