host posted on May 05, 2008 20:02
This article investigates the most common causes of errors in measurements performed with electrostatic fieldmeters and presents methods and arrangements which minimize or eliminate those errors.
The charged flat surface represents a very common object of electrostatic measurements, for instance:
- In investigation of electrostatic hazards in industries such as plastics, textiles, graphic arts, film and paper converting and electronics.
- In various static decay tests.
- In calibration of electrostatic fieldmeters.
Measurements of electrostatic fields are made with the help of various types of noncontact electrostatic fieldmeters, with two better known: electrometer type instruments and chopper stabilized or “field mill” type instruments.
The simplified block diagram of an electrostatic fieldmeter is shown in Figure 1. C1 is the capacitance between the charged surface and the sensing electrode. C1 is maintained constant in electrometer type fieldmeters. C2 is the capacitance to ground of the sensing electrode and is constant.
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