1J46 and 1j50 have a secondary magnetic field is used in all kinds of transformers, relays, electromagnetic clutch, choke coil and magnetic circuit parts of iron core, pole shoe, headphones diaphragm, earth-leakage circuit for relay parts, safety valve, magnetic shielding gas, gyroscope, synchro motor, micro motor electronic watch, etc.

1J17 and 1j85 have high initial permeability and maximum magnetic permeability, low coercive force, low saturated magnetic induction. Weak magnetic field is used in high sensitivity and small power transformers, relays, magnetic amplifier, choke coil, magnetic recording system with magnetic head, magnetic shielding, all kinds of belt around the iron core, cut iron core and laminated iron core, etc.