Dust test results on multicontact circuit board connectors

A study to determine if the normal force of a connector is a factor in maintaining a low contact resistance after an accumulation of dust in the pins and receptacles is discussed. A dust mixture of hygroscopic salts and natural mineral particles was used. The test connectors included the standard 2-mm connector with a nominal normal force of 0.55 N, a special 2-mm connector with an extra low normal force of 0.35 N, and another connector with a normal force of about 1.5 N. Resistance values, as compared with values measured before the dust exposure, increased by less than 4 mΩ for the contact pair showing the largest increase. The results indicate that the lower normal force in high-density connectors does not adversely affect the ability of the connector system to tolerate particulate contaminants