Patent GB-732437-A (GB)
Title: Electric circuit components
Inventor: EISLER PAUL
IPC: H01C17/23
Filed: 1951-10-03
Abstract: 732,437. Printed circuits; fixed resistors; capacitors. TECHNOGRAPH PRINTED CIRCUITS, Ltd. Oct. 2, 1952 [Oct. 3, 1951], No. 23098/51. Classes 36 and 37. An electric circuit component comprises at least two separate highly conductive areas each having several branches, which are connected by a multiplicity of paths of electrically active material (i.e. resisti ve, semi-conduetive or dielectric material), the conductive and electrically active elements being arranged to provide a region in which the component can be mechanically stressed (i.e. bent, folded, rolled or cut) without significantly altering the electrical values of the effective paths of the electrically active material. The electrical value of the component as a whole may be altered by severing a highly conductive area in the said region. The highly conductive parts of the component are preferably made from metal foil by the method disclosed in Specification 639,178. A resistive or semi-conductive component may consist of a flexible insulating base 10 carrying two highly conductive areas on one surface. The conductive pattern comprises two parallel stems 11, 12, each having branches 13A-13D and 14A-14D respectively, which are spaced apart as shown in Fig. 9. A band 15 of resistance material bridges and makes contact with the conductive branches and is spaced from the stems 11, 12, the component thus comprising a number of parallel resistance units between terminals 16, 17. The resistance of the whole component may be varied by cutting off a portion of the unit or by severing one of the stems or one or more of the branches, or by reducing the length of one or more of the branches. Alternatively, some of the branches may be severed as illustrated, and slits such as 23, 24, 25, made parallel to the stems to form a meandering resistance. When the component is to be folded any portion of the resistance bands where a fold is to be made may be rendered ineffective by severing the appropriate branch so that any damage to that portion of the resistance band will not affect the resistance of the component. Alternatively, one of the branches may be duplicated so that the resistance material between its two limbs is always ineffective. If the component is to be rolled a layer of metal foil of high thermal conductivity may be provided on the underside of the insulating base so that heat will be conducted away from the inside of the roll. Instead of the band 15 of resistance material, an insulating tape carrying several resistance bands or lines may be used, the lines being straight (Fig. 11) or zig-zag, or forming a pattern of cycloids. This provides a grid-like arrangement of resistors, the value of the component being variable by severing the conductive pattern at desired points between the bands or lines. One of the conductive stems may be carried on the under surface of the base 10, connections being made to the appropriate branches through perforations in the base by means of eyelets or staples. The support 10 may be dispensed with and replaced by a sheet 73 (Fig. 30), of resistance material, overlapping highly conductive areas 74 and 76, connected together by severable links, being formed on opposite sides thereof to produce a plurality of series-connected resistor units. A capacitor component (Fig. 27) may comprise an insulating base 10 carrying conductive stems 11, 12 having branches 68, 69 respectively. The branches are bridged by a band 70 of dielectric, which may include high permittivity material as disclosed in Specification 690,360, and a conductive band 71 is placed thereover. The base 10 may be made of dielectric material and have a further conductive band on its underside. The component may be treated as described in Specification 690,328. The component comprises a number of capacitor units connected in parallel, and the total capacity of the component may be adjusted by cutting off a portion or by severing one or more of the branches or stems. The above components may be incorporated in a printed circuit 85 (Fig. 34), preferably being formed on extensions 87, 88 of a flexible support 86, so that after adjusting to the required value they may be rolled or folded to lie within the limits of the main part of the circuit. Specification 639,111 is referred to in the Provisional Specification.