The desing of simple instruments for measurement of charge on insulating surfaces

Abstract The principal design considerations for two distinct types of charge sensing instrument are outlined. The first instrument reviewed is the electrostatic field mill (generating voltmeter) which measures the resultant field due to the charge on a surface area typically of a few square centimeters. The second instrument discussed is the screened potential probe which can be scanned over a sample surface to provide an indication of charge magnitude and spatial distribution. It is shown that the required operating criteria for these instruments can easily be satisfied using solid-state devices in essentially simple circuits.