Electrostatic Field Tester Usage Instructions and Precautions
1. Before measurement, first check whether the power supply meets the specifications, whether the instrument casing (including the probe's outer shield) is properly grounded, and the instrument must be zeroed before testing.
2. The test probe should not be placed in a spatial position perpendicular to the surface of the charged object being measured (according to the test distance specified in the instrument's instructions). Variations in the test distance will introduce significant test errors. To avoid spark discharge between the charged object and the probe casing, the probe must be placed at a relatively far position (away from the charged object) at the beginning of the measurement, gradually approaching the charged object.
3. When testing surface potential, the surface of the charged object should generally be sufficiently far from the grounding electrode. If the charged object is a thin sheet or film, and its back side is close to the grounding electrode, when the probe is moved near the grounding electrode, there is a risk of spatial discharge or surface discharge due to the induced concentration of local charges.
4. When the measured part of the charged object is a large flat plate, the measurement value is relatively accurate. However, when the surface of the charged object has a certain radius of curvature, the measured value will differ significantly from the actual potential value.
5. The influence of the instrument's own characteristics on the testing accuracy should be considered. Regular calibration and standardization should be performed before use.
6. The probe shielding depth has a certain impact on the testing accuracy. Inductive electrostatic field testers essentially test the local electric field of a charged object; therefore, it is essential to minimize the interference and influence of external electric fields on the test signal. The common method is to install such instruments and their probes in a grounded shielded housing. Obviously, an excessively deep outer shielding sleeve will reduce the instrument's testing accuracy, while an excessively shallow one is easily affected by external electric fields.
7. The value obtained by testing the surface potential of an object can be used as a qualitative reference. Precise measurement is difficult to achieve in practical work due to various factors.
8. Electrostatic voltmeters used in the electronics industry typically need to consider testing accuracy and should be able to measure electrostatic voltages within ±10V.