Hajime Tomita

Influence of rise velocity of charge voltage on spark discharge from a metal sphere

Electrostatic discharge (ESD) is an electromagnetic disturbance source. ESD is usually generated as a form of spark discharge that occurs in the air gap between a charged body and a grounded one. The characteristics of a spark discharge depend on the humidity, the moving speed of a charged body to a grounded body, and the structure of a charged body. An ESD event in the time during which a charged body moves toward a grounded body has a more significant effect on electronic equipment than an ESD event from a stationary charged body with the same charge voltage. This peculiar phenomenon is not well understood due to reasons such as the difficulty of reproducibility. To further the understanding of the ESD, the influence of the rise velocity of the charge voltage on ESD from a stationary metal sphere was measured in the gap length between 20 and 80μm. The results of the experiment indicated that in instances where no sparking discharge occurred, at the same gap length the maximum voltage-charge value became higher with the rise in the charge-voltage velocity. In instances where the sparking discharge occurred for all applied charge voltages under each discharge condition, the average value of the sparking voltage increased with the rise in velocity of the charge voltage for the same gap length.