Accession Number : ADD003313

Title :   Surface Impedance Tester.

Descriptive Note : Patent,

Corporate Author : DEPARTMENT OF THE AIR FORCE WASHINGTON D C

Personal Author(s) : Robinson,Wesley A ; Madle,Peter J

Report Date : 30 Nov 1976

Pagination or Media Count : 8

Abstract : The patent relates to measuring the permeability and resistivity of metal sheets including those installed in enclosing structures. They are nondestructively determined by injecting a unit-step pulse of current into an exposed surface of the sheet and measuring the surface voltage gradient between a pair of contacts located between the current injection contacts. The permeability and resistivity of the metal determines the rate of diffusion of current into the surface and therefore the rate of decrease of this surface voltage gradient. At steady-state the current density will be uniform throughout the thickness of the sheet resulting in the surface voltage gradient stabilizing at a value depending on the resistivity and thickness of the metal.

Descriptors :   *Measuring instruments, *Patents, Electrical impedance, Permeability, Sheets, Iron alloys, Steel, Structures, Surface properties, Electrical measurement

Subject Categories : Test Facilities, Equipment and Methods

Distribution Statement : APPROVED FOR PUBLIC RELEASE