Aluminum cladding thickness measurement probe and instrument having an automatic calibration and readout circuit coupled to a differential amplifier circuit

摘要

A system for measuring the cladding thickness on aluminum sheets which includes a cylindrical probe holder with four evenly spaced contact points surrounding a low temperature coefficient torroidal ferrite core which provides a signal to an aluminum cladding thickness signal processing circuit comprising a crystal oscillator, low drift detector, and push button calibration instrument portion thereby enabling drift free repeatable measurements.