Characteristics of E-field near indirect ESD events

In the indirect electrostatic discharge (ESD) event, the shape of electromagnetic pulse due to discharge is important for estimating the performance degradation of electronic equipment. The pulse shape of the electric field was observed in the proximity of a conductor plate at which contact discharge was taking place. The results show that the pulse shape is affected by the location of both the discharge point and the connection point of the current-return cable. The results indicate that the immunity test for the indirect ESD should be done varying the point and direction of discharge