RHEOSTAT FOR HIGH VOLTAGE

PURPOSE:To simplify structure, to confirm a design and reliability in a short time and to obtain a low-cost rheostat having high reliability by composing the rheostat of a cap-shaped case holding a shaft with a slider, a resin board sustaining an insulating substrate and a resin layer, etc., covering an electric active section and ensuring insulating properties with the outside. CONSTITUTION:A rheostat consists of an insulating substrate 1, on a surface of which a resistor section 1a and electrode sections 1b connected to the resistor section 1a are formed, a resin board 3, to which ribs 3a abutted against approximately the outer circumference of the insulating substrate 1 are formed, terminals 4 connected to said electrode sections 1b and a cap-shaped case 7, one end of which is formed in an opening shape and a bottom section of which has a through-hole 7b and in which a shaft 5 with a slider 6 slid on the resistor section 1a is mounted rotatably to the through-hole 7b. Said insulating substrate 1 is installed to said resin board 3 while the resistor section 1a is positioned on the outside, the case 7 is set up to the insulating substrate 1 while the slider 6 is abutted against the resistor section 1a, the terminals 4 and the electrode sections 1b are bonded, and the resistor section 1a, to which at least high voltage is applied, and the bonding sections of the electrode sections 1b, to which high voltage is applied, and the terminals 4 are covered with a resin 8.