Effects of joints on contact reliability in miniature precision snap-acting switches

The results of a study examining to what extent the joints of a miniature precision snap-acting switch affect the contact reliability of the switch are reported. The results revealed that in a sample which incorporates a movable contact blade and a movable spring (both of which are made of phosphor bronze), a common terminal made of silver-plated brass, and gold crossbar contacts, the joints were responsible for more than 80% of the rise in the contact resistance of the switch in each of the mechanical life, minute load, sulfurated gas resistance, and high-temperature/moisture resistance tests. The contact surface of each joint constantly changes with the action of the switch, and by its sliding action oxide due to abrasion is apt to be generated.<>