Design and development of an electrostatic voltmeter based on surface potential sensor

This paper deals with the design and development of an electrostatic voltmeter based on surface potential sensor. For the realization of the device, constructed by us, a surface potential measuring sensor EFS-22D has been used, consisting of a measuring probe and an electronic converter for measuring voltages in the range from 0V to 900V at a distance between the sample and the surface of the probe within 1 – 3.5mm. The measuring probe is composed of an oscillating mechanism (of the type of a tonometer), with metal electrodes attached to it, which block the electric field. The movement of these electrodes is accomplished by means of a piezo-electric element. The chopper is tuning fork oscillator type shutter. The surface potential, measured by the probe of the sensor, is converted into analogue voltage, varying from 0 to 4.5V, which is then converted into a digital value by a 15-bit sigma-delta analogueto-digital converter, connected to a microcontroller. The data from the measurements are transmitted from the microcontroller to a personal computer through a Bluetooth module. User software has been developed, allowing for: recording the obtained values from the measurements; their visualization both in digital and analogue form; digital filtration of the noise from the sensor; and statistical analysis of the obtained data