Comparison of vibrating and fixed Kelvin probe for non-destructive evaluation.

This paper presents a comparative study of surface electrical potential measurement carried out with the classic vibrating Kelvin probe and with the newly designed swing capacitor transducer. Mathematical modeling and experimentation demonstrated that the non-vibrating swing capacitor probe is notably more sensitive (in some instances more than six times) than the vibrating Kelvin probe in cases where space charge is buried under dielectric layers with slow polarization. This provides an advantage in multi-layer structures, for example, to detect and localize corrosion under paint.