Investigation of Broadband Electrical Contact Performance of Electrical Connectors Under Repeated Plugging and Unplugging Operations

The wear of the contact surface caused by relative sliding can degrade the electrical contact performance of the aviation electrical connector. This work mimics contact surface wear through repeated plugging and unplugging experiments. A noncontact in-circuit impedance measurement method using a dual inductive probe technique is employed to continuously measure the impedance of the circuit under test, which comprises the connector and connecting wire, across the 1–150-MHz frequency range during the experiment. Subsequently, the electrical parameters of the degraded connector are determined by combining a lumped transmission line model of the connecting wire with a broadband impedance model of the connector, based on the measured impedance of the circuit under test. The experimental results indicate that as the number of plugging and unplugging cycles increases, the resonant frequency observed in the broadband impedance measurements decreases. This phenomenon is primarily attributed to an increase in the contact capacitance of the connector due to wear on the contact surfaces. After 2000 test cycles, the resonant frequency of the circuit under test decreased by 1.25 MHz. Parameter identification revealed that the contact capacitance of the connector increased from 11.6 to 48.9 pF, a 4.22-fold rise. Meanwhile, the dc contact resistance increased by only 1.15 times over the same period. These findings suggest that contact capacitance is a more sensitive indicator of early degradation than dc contact resistance.