The common transformer core is generally made of silicon steel sheet. Silicon steel is a kind of steel containing silicon (silicon is also called silicon), and its silicon 

content is. 0.8%~4.8%。 The reason why silicon steel is used as the iron core of transformer is that silicon steel itself is a magnetic material with strong magnetic 

conductivity. It can produce large magnetic induction intensity in the energized coil, which can reduce the volume of transformer. The power loss of transformer 

under AC state is not only on the resistance of coil, but also in the iron core under alternating current magnetization. The power loss in the iron core is usually called 

"iron loss", which is caused by two reasons, one is "hysteresis loss" and the other is "eddy current loss".

Hysteresis loss is the iron loss caused by the hysteresis phenomenon in the magnetization process of the iron core. The size of this loss is directly proportional to the 

area surrounded by the hysteresis loop of the material. The hysteresis loop of silicon steel is narrow. The hysteresis loss of the iron core used as a transformer is small, 

which can greatly reduce its heating degree.