Characteristics of Electric Charges Carried by Dust Particles and Their Effects on Connector Contact Failure

Dust contamination is one of the major causes of electrical contact failure in the electronic system. This paper describes the characteristics of electric charges carried by dust particles and their effects on connector failure. A Millikan testing method was used for measuring the electric charges. The results show that the variation of electric charges carried by dust particles is located in a band region, and the trend of charges can be expressed as a third order equation. The morphology and surface seem to be the major factors which influence the electric charge. It is found that dust particles carry negative charges or positive charges, these particles will be attracted to both electric contact surfaces in connector respectively, and thereby increasing the probability of connector failure. The selective deposition of particles was found on electric contact surface. The failed connectors were investigated by using SEM/EDS (Scanning electron microscope and Energy dispersive X-ray spectroscopy) and protection from dust particles was recommended.