Normally need to use the cause of the low permeability core is what?

Normally need to use the low permeability core. For two reasons: one, of low permeability cores usually has high Curie temperature. They are running at high temperatures and not lose its magnetism. Second, the low permeability core has high characteristics under a given frequency. This means that the impedance is most associated with nondestructive reactance, rather than the dissipative resistance. They will be a smaller proportion of the power is converted to heat, this important at high power levels. Permeability changes with frequency. With the increase of frequency from zero, the final core impedance peak. On the peak of the impedance frequency, the impedance of the core ( And the effective permeability) Actually reduced. With the increase of frequency, magnetic permeability decline slope is useful for a broadband impedance of transformer control, but we should be careful to avoid excessive slope. Too much of the initial permeability is easy to make the work area in the impedance of the slope of the down too far. Excessive use of the initial permeability means the winding become tedious ( Need more turning) 。 Wires need to be small and vulnerable to fit into the core of the given window. Temperature stability can be reduced, and loss will increase with the preferred core material selection. In addition, do not need to increase the stray capacitance, reduce the bandwidth and increase the unwanted stray coupling. Good design will be the conductor length is placed within the magnetic core window, small conductor length in the core outside the window.