An Instrument for Measuring the Thickness of Thin Nonmagnetic and Nonmetallic Coverings on a Ferromagnetic Base

摘要

The object of the invention is an instrument for measuring the thickness of thin nonmagnetic and nonmetallic coverings on a ferromagnetic base, which contains a generator, measuring and compensating bridges, a resonance amplifier, a resonance cascade, two detectors, a summing block and a measuring instrument. To exclude the effect of a change in the magnetic permeability of the base upon the accuracy of the measurements, the measuring bridge with inductive transducers and balancing elements is connected to the inputs of a two-channel resonance amplifier whose first channel is tuned to the third harmonic of the generator frequency and the second channel is tuned to the basic frequency of the generator. (Author)