| 摘要 |
<p>Prevention of deposits due to arcing of switch contacts sliding over printed conductors of control unit for indicators and warning light of cars is ensured by the design of the circuit board. A polyester film is coated between the printed conductors (24-28) and the board (14) where grooves (33) separate the conductors and hold a spark quenching material. The separation of the conductors protects the board against heating caused by the arcs which tends to soften the board and make ineffective the contact between the wiper and the conductors. The reliability of a contact carrier is enhanced and the service life of the switch is extended.</p> |
