| 摘要 |
<p>PURPOSE:To prevent accelerated corrosion at a part where bias is to be applied by providing a physical isolation plate between patterns formed on a printed circuit board(PC board), arranging ring conductors around the isolation plate and connecting the ring conductors so that they have higher potential than the isolation plate. CONSTITUTION:A PC board 25 is disposed at the joint of a tubular body 7 and a cable ground 9 and connected with a conductor 14. An isolation plate 26 is provided between the conductors 14 and an insoluble ring conductor 27 composed of a thin platinum film is arranged around the isolation plate 26. An electric circuit 30 is connected so that the conductor 27 has higher potential than the isolation plate 26. The PC plate 25 is connected with a PC plate 17 through a connector 16. This structure ensures the creeping distance between conductors 14a, 14b by means of the isolation plate 26. Since the ring conductor 27 held at a higher potential is arranged around the electrical joint, surface leak current between the conductors 14 due to high humidity is prevented and the leak current to the surface of the tubular body 7 is blocked thus preventing the accelerating corrosion.</p> |
