Is there a magnetic material 800K with high permeability at high frequencies and low permeability at low frequencies in 50Hz?
Impedance Z= Omega L, the angular frequency of Omega input voltage, Omega =2 PI f; so Z is proportional and frequency is obvious. L=N^2/Rm, inductance value N^2: inductance, the number of turns on the loop. Rm: magnetic resistance Rm=l/ mu S L: inductance magnetic circuit length, S: inductance magnetic circuit cross section Mu: permeability
Some nickel zinc material will have such characteristics, manganese zinc, iron powder core in more than 1MHZ, there is no magnetic
