New type micro cloth-inductor and transformer with thin amorphous wires and multi-thin coils

Abstract

The authors report miniaturization along with high resonant frequency and high quality factor in a wide frequency range of a cloth-inductor and high coupling coefficient and current capacity in a cloth-transformer. To reduce the eddy current loss of the magnetic core, ultrathin amorphous wires are made by chemical etching. These wires are bounded by multithin exciting copper wires 15-50 mu m in diameter. The number of cores and windings of coils are varied in the range of 3 to 5 and 7 to 30, respectively. A piece of core is a bundle of 100 or 400 Co-base amorphous wires 30 mu m and 5 mu m in diameter, respectively. The cloth-inductor with three cores is a bundle of 400 amorphous wires 5 mu m in diameter, and the coil is a bundle of six copper wires 20 mu m in diameter, showing an inductance of 1.2 mu H. The Q is higher than 20 in the frequency range from 1 to 20 MHz. The maximum Q is 40 at 5 MHz. These multithin coil inductor are easily modified to make a transformer. The coupling coefficient and current capacity are 0.95 at 8 MHz and 190 mA, respectively.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>