Abstract: A current transformer for alternating current with direct current components is proposed, consisting of at least one transformer core with a primary winding and at least one secondary winding to which a burden resistor is connected in parallel and terminates a secondary circuit with low resistance. The transformer core comprises a closed ring core with no air gap produced from a strip made of an amorphous ferromagnetic alloy that is practically free from magnetostriction and has permeability &mgr;<1400. Particularly appropriate alloys for such a strip ring core have been shown to be cobalt-based alloys consisting essentially of the formula Coa(Fe1-xMnx)bNicXdSieBfCg. where X is at least one of the elements V, Nb, Ta, Cr, Mo, W, Ge and P, a-g are given in atomic % and whereby a, b, c, d, e, f, g and x satisfy the following conditions: 40≦a≦82; 2≦b≦10; 0≦c≦30; 0≦d≦5; 0≦e≦15; 7≦f≦26; 0≦g≦3; with 15≦d+e+f+g≦30 and 0≦x<1.

Abstract: Low-pass filter for a diplexer in an ADSL communications system comprising a low-pass filter (8) with chokes (9). Said chokes (9) have magnetic cores made of an alloy, especially a nanocristalline or amorphous alloy.

Abstract: Magnetic cores including coiled amorphous ferromagnetic alloy strips in which at least fifty percent of the volume contains fine crystalline particles with an average particle size of 100 nm or less are addressed. The composition of the alloy essentially corresponds to the formula FeaCobCucSidBeMf, where M is at least one of the elements V, Nb, Ta, Ti, Mo, W, Zr, and Hf; and a, b, c, d, e, and f are indicated in atom percent and meet the following conditions: 0.5≦c≦2; 6.5≦d≦18; 5≦e≦14; 1≦f≦6; with d+e>18 and 0≦b≦15, and a+b+c+d+e+f=100.

Abstract: In an ISDN digital communications system, the transmission between the network termination and the terminal equipment ensues via what is referred to as the S.sub.o interface, on the basis of interface transformers. Since the power supply of the terminal equipment likewise partly ensues via these transformers, a current asymmetry in the lines results in a pre-magnetization of the transformers. Thus, the ISDN demands made of the transformers must also be satisfied given a DC pre-magnetization. Compact transformers having a simple winding format that satisfy the ISDN demands are set forth, the transformers utilizing a magnetic core having a fine-crystalline iron-based alloy with an iron part of more than 60 atomic %, the structure thereof being more than 50% fine-crystalline grains having a grain size of less than 100 nm and having a remanence ratio of less than 0.2 and a permeability in the range from 20,000 to 50,000, and an inductance of less than 100 pF.