Target Material and Thickness
The sensor’s electric field seeks a conductive surface, meaning that these transducers are not affected by target material (magnetic, nonmagnetic) provided that it is a conductor. Because the electric field resides at the surface of the conductor, target thickness is not important.
Environment
Although capacitive transducers are not affected by material magnetic properties, they are sensitive to the medium in the gap between the sensor and the target. Maintaining a steady dielectric constant in the gap is therefore important—and humidity affects the dielectric constant of air. The dielectric constant of air increases with humidity and will change the capacitance between sensor and target.
Furthermore, moisture and other fluids can migrate into the sensor and negatively interact with its construction. Capacitive transducers are therefore not recommended for applications characterized by excessive dirt, dust, water, machining fluids, or oils.
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