| 摘要 |
PURPOSE:To obtain a through type capacitor wherein the tracking resistance has been improved, by a method wherein the surface of an insulating sheath case provided around the dielectric and the part through which the central conductor is passing through is covered with an insulating resin film having a good tracking resistance. CONSTITUTION:In a through type capacitor, the outer surface of a sheath case, particularly 4, made of polybutylene terephthalate (PBT) os easy to be contaminated during the handling such as the equipment assembling work (although a sheath case 5 is also made of PBT, it is relatively difficult to be contaminated), so a creeping discharge is easy to occur when a high voltage is applied to a central conductor 2. The PBT, the material for the sheath case, is fairly good in tracking resistance, but, while a creeping discharge is repeated several times during a long period of time, free carbon occurs along the discharge path, that is, a tracking occurs, so that a discharge may occur even at a relatively low voltage. To prevent this phenomenon, the outer surface of the sheath case 4 is covered with an insulating resin film 41 having a good tracking resistance. With this, a creeping discharge is prevented form repeatedly occurring at the same path, whereby the withstand voltage characteristics of a through type capacitor can substantially be improved.
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