... and high permeability, super low coercivity and low saturation magnetic induction. Fe-Ni Soft Magnetic Alloy (Permalloy) Core 1. Material Grade: 1J50,1J79 ... sequence current transformer, power converter, precision current transformer, magnetic amplifier, power transformer, choke, pulse transformer, change polarity ... to the user’s actual usage requirements. Fe-Ni Soft Magnetic Alloy (Permalloy) Core