Abstract:
A magnetic composite for AC applications with improved magnetic properties (i.e. low hysteresis losses and low eddy current losses) is disclosed. The composite comprises a consolidation of magnetizable metallic microlamellar particles each having a top and bottom surfaces and opposite ends. The top and bottom surfaces are coated with a dielectric coating for increasing the resistivity of the composite and reducing eddy current losses. The dielectric coating is made of a refractory material and the ends of the lamellar particles are metallurgically bonded to each other to reduce hysteresis losses of the composite. A process for manufacturing the same is also disclosed. The composite is suitable for manufacturing devices for AC applications such as transformers, stator and rotor of motors, generators, alternators, field concentrators, chokes, relays, electromechanical actuators, synchroresolvers, etc....
Abstract:
A method for preparing a composite soft magnetic sintered material, which comprises admixing a composite soft magnetic powder comprising a Fe−Co based soft magnetic alloy powder and, applied on the surface thereof, a ferrite layer coating having a spinel structure with a silicon dioxide powder having an average particle diameter of 100 nm or less in an amount of 0.05 to 1.0 mass %, forming by pressing the resultant mixed powder, followed by sintering, or comprises admixing two or more types of composite soft magnetic powder comprising a Fe−Co based soft magnetic alloy powder and, applied on the surface thereof, two or more types of ferrite layer coating having a spinel structure which have different chemical compositions from one another, forming by pressing the resultant mixed powder, followed by sintering. The composite soft magnetic sintered material exhibits a high density, an excellent mechanical strength and further a high specific magnetic permeability even in a high frequency.
Abstract:
An economically advantageous process for producing sintered magnetic Fe-Co, Fe-Co-V or Fe-Co-Cr material, which comprises preparing alloy powder of at least Fe and Co, kneading it with an organic binder, subjecting the kneaded mixture to injection molding and degreasing, and conducting two-stage sintering at both low and high temperatures is disclosed. A magnetic material having excellent magnetic properties and low iron loss value and comprising a specific composition of Fe-Co, Fe-Co-V or Fe-Co-Cr is also disclosed.
Abstract:
위상 변환기를 이용해 잡음을 제거한 저 잡음 증폭기가 제공된다. 본 발명의 실시예에 따른 저 잡음 증폭기는, 입력 신호를 증폭하는 제1 증폭부와 제2 증폭부, 제1 증폭부에서의 증폭 신호와 제2 증폭부에서의 증폭 신호를 합하여 출력하는 출력부 및 제1 증폭부의 입력단에서 잡음 전류의 위상을 변환하여 제2 증폭부에 입력시키는 제1 매칭부를 포함한다. 이에 의해, 증폭기를 크기가 작은 트랜지스터들을 갖는 소규모 증폭기들로 분할하고, 위상 변환을 위한 매칭 회로를 이용하여, 증폭기들의 잡음을 줄이고 서로 상쇄시킬 수 있게 된다.