The thickness gauge is a measuring instrument used in industry and mechanical technology, which allows you to measure thickness.
The thickness gauge is a term that encloses types of instruments also very different between them, both those intended to thickness measurements external (eg. plates, sheets), both those intended to measures of internal thickness (eg. quarries, cracks).
The most used thickness gauge are the ultrasoun or the magnetic type. The thickness gauge ultrasonic are based on reflection that the waves emitted by an ultrasonic generator, put on a face of the object to be analyzed, undergoes on the opposite face; for the measurement, it must be noted the speed of propagation of sound in the material of which is made the object.
The magnetic thickness, designed to measure the thickness of the cover, made with painting plating, etc.. on ferromagnetic materials, detect the reluctance of the magnetic circuit consists of a coil carried by a probe, the thickness of the coating (which is a material with low magnetic permeability and therefore presents a high reluctance) and the piece of ferromagnetic material.