Charge decay measurements for characterising static dissipative materials

Describes the design, operation and performance of a new type of instrument for the assessment of the static charge dissipation characteristics of materials. The approach described is more appropriate than the conventional measurement of resistivity because it observes directly the charge retaining features of the surface whereas resistivity measurements respond only to conducting features present on a surface. This involves depositing some static charge on the surface (for example by corona discharge) and then using an electrostatic fieldmeter for noncontact observation of the rate of charge dissipation and the time for the surface potential or surface charge density to fall to a suitably low value