Radio interference suppression choke for semiconductor circuits - esp. for lighting dimmers, and using multilayer iron core

摘要

The circuits esp. use phase control; and the choke consists of a ring core with an insulated wire winding. The core uses >=2 components (A, B), where (A) is a compact of ferromagnetic powder (A1) and an insulant, whereas (B) is also ferromagnetic powder (B1) with a different amt. of insulant. Component (A) pref. contains 0.05-4 wt.% insulant, whereas component (B) contains below 0.04% insulant. Both powders (A, B) are pref. pure Fe, size 10-500 mu m, esp. Fe (A) of 10-100 mu m, and Fe (B) 100-500 mu m. Powderers are pref. pressed in the sequence (A, B, A). The insulant is pref. water-glass; silica flour; or kaolin. Alternatively, (A) is an alloy contg. max. 82% Ni, max. 5% Mo; and (b) is an alloy contg. max. 10% Si. Used esp. in dimmer circuits for reducing light intensity, using thyristor-triac elements, e.g. to obtain from 600 to 60 watts, where the choke is used with a capacitor.