The disclosure discloses a magnetic unit, which includes a first ferrite core component, a second ferrite core component and a winding. There is a first hollow portion within the first ferrite core component. The second ferrite core component is disposed in the first hollow portion. There is a second hollow portion within the second ferrite core component. Magnetic saturation characteristics of the second ferrite core component are better than magnetic saturation characteristics of the first ferrite core component. The winding is wound on the first ferrite core component and the second ferrite core to component.