Measurement Methodologies for Analysis of Electrostatic Discharge Events in Multibody Problems

Maxwell's method to formulate multibody capacitances for a system of conductors is the preferred method for use in the analysis of electrostatic discharge (ESD) events in multibody problems since the effect of external ground planes is included in the concept of capacitance coefficients. For any geometry of conductors and body charges, body potentials can be calculated to determine the relative probability and severity of an ESD event. However, the measurement method to determine capacitance coefficients requires the use of a stable dc supply and a floating battery-powered electrometer. In this paper, an alternate measurement methodology is investigated which uses a conventional capacitance meter. Body-to-ground and body-to-body capacitances are measured; transformation equations are developed which permit the calculation of the required system capacitance coefficients. The two methodologies are compared with measurements done on a basic two-body problem including a ground plane.