| 摘要 |
1,080,896. Resistors. IRC Inc. Jan. 6, 1966 [Jan. 21, 1965], No. 689/66. Heading H1S. An electrical resistor 10 (Fig. 1) comprises a solid cylindrical ceramic substrate 18 whose cylindrical surface is coated with a resistance film 20, terminated at each end of the substrate by a metal film 22 coated with solder 24 to secure the flat bead 28 of a terminal wire 26, the assembly being jacketed in plastics material. Mass production of such resistors comprises the following stages: (1) A number of ceramic rods are coated (dipped, sprayed or painted) with a resistance film (carbon, metal, alloy or mixture of metals per se or dispersed in a glass or plastics binder) then encapsulated in spaced parallel relation in a block of plastics material (e.g. various resins or waxes). (2) The block is then cut perpendicular to the rod axes to form wafers which are then immersed in a solvent to controllably dissolve the plastics of the wafer to expose the ends of the rods and films. (Solvents suitable for the various plastics material are disclosed in the Specification.) (3) After washing, the wafers are coated entirely with copper or nickel (for example by electroless plating) and re-immersed in solvent then washed, to remove the metal covering the plastics so that only the ends of each rod and resistance film are coated with metal. (4) The metal-coated ends are dipped in solder and the resistance elements separated by dissolving all the plastic in solvent. (5) Terminal wires are attached by abutting the circular heads of the wires against the soldered ends of the resistance elements and applying heat, e.g. by passing the assembly on a conveyer through a furnace. (6) Finally an insulating plastics jacket is moulded, cast or coated around the resistance element. |
