At first, silicon steel sheet core was mainly used for power transmission and instrument equipment. In these two occupations, the shapes are basically similar and the data are obviously different. The silicon steel sheet core for power transmission is mostly ultra-thin silicon steel sheet core, which has the characteristics of full BS and magnetic induction intensity of about 2T; The silicon steel sheet of the instrument is ferrite core, which has the characteristics of full BS, and the magnetic induction intensity is about 0.3T.

Silicon steel sheet is used for communication, the communication frequency is uneven, and the silicon steel sheet core cannot be filled during operation. In the early stage, when transmitting power, the silicon steel sheet operated at power frequency. The frequency of 50 / 60Hz was relatively low, but the operating current was relatively large. The loss is mainly concentrated in copper loss. Due to the large current, the total magnetic induction intensity of silicon steel core data is large.

Later, silicon steel sheets were invented as data for power transmission. The iron core of silicon steel sheet can meet the requirement that the iron core is not full under the condition of low-frequency and high current operation. Therefore, because the ultra-thin silicon steel core has high magnetic saturation strength, it plays an important role in power transmission alone.

With the increase of electrical equipment, there is more and more demand for power supply and higher requirements for power quality. Power development from the original silicon steel sheet rectification or voltage conversion, to linear power supply, and then to switching power supply. Silicon steel sheet for switching power supply is characterized by low working current and convenient power transmission. However, in order to improve the effectiveness of the power supply and reduce the size of the power supply. The working frequency of silicon steel sheet of switching power supply is 20K ~ 200K.

If the silicon steel sheet core is used as the original silicon steel sheet, its resistivity is very small. At high frequency, eddy current loss is an important factor affecting the application of switching power supply, and the actual heating requirements are strict, which affects the application of silicon steel sheet in switching power supply. Therefore, the ferrite core data appears. It is characterized by low magnetic saturation intensity. However, for the switching power supply, it is basically dissatisfied. Its main advantages are that the resistivity of silicon steel sheet is greatly improved, the eddy current loss is reduced, the heating is no longer so strict, and there is basically no problem in the process of practical application.