GB1180923A - Improvements relating to Electric Coil Assemblies. - Google Patents

Abstract

1,180,923. Transformers and inductors. PLESSEY CO. Ltd. 13 Feb., 1967 [21 Feb., 1966], No. 7479/66. Heading H1T. A pot core assembly comprises a coil in the form of a conductive pattern on a substrate. The coil may be formed of a number of interconnected sets 3 (Fig. 1b) of spiral or part circular step turns etched from copper cladding on both sides of a resin bonded glass fibre strip 1. The strip may be folded as shown, part cured glass fibre washers 12 separating adjacent sets of turns, the whole being consolidated to a solid block by heat and pressure. The tubes may be provided on one side only of the glass fibre substrate, may be deposited and form separate windings and may be of aluminium or silver. Glass fibre washers may be selected of suitable thickness to give a desired temperature coefficient. The coil may be produced by a repeated process of deposition of turns followed by application of insulation over each set of turns. Fig. 3b, shows a coil combined with a pot core comprising a ferrite base 51 having upstanding parts 53 which pass through the substrate 47 to contact upper core disc 52. Tuning is by movement of embedded ferrite slug 59 or can be effected by having parts of the upper core disc cut away (56, Fig. 3c, not shown) and arranging it for rotation relative to the core base. Tapping as well as terminal connections may be provided and the apparatus may form an I.F. transformer.