The silicon steel core are suitable for the application in weak magnetic field, can be used for manufacturing high sensitivity and small power transformer, low power magnetic amplifier, relay, head of magnetic recording device, zero sequence current transformer, power converter, precision current transformer, magnetic amplifier, power transformer, choke, pulse transformer, change polarity pulse transformer, DC voltage converter, magnetic modulator, constant inductance element, unipolar pulse transformer, magnetic shielding, and so on.