Patent Document ID: 5517110
Application ID: 08417900
Patent Status: 1

Claim One:
1. A method for testing an unpopulated or inactive populated printed circuit board (BUT)including electrically conductive paths, parts and surfaces whose electrical and physical continuity and conformance to a known standard is to be verified, the BUT having a first side and an opposite side, the method comprising the steps of: a) providing electromagnetic signal applying means without electrical contact with said BUT, wherein said electromagnetic signal applying means comprises at least one stimulator located adjacent to said BUT on said one side thereof; (b) providing power to said electromagnetic signal applying means with an AC signal generator such that said stimulator radiates an electromagnetic field onto said BUT, which induces currents and charges on said electrically conductive paths, parts and surfaces of said BUT which establishes an electromagnetic potential along said electrically conductive paths, parts and surfaces; (c) providing ground reference plane means on said opposite side of said BUT with respect to said at least one stimulator, wherein said ground reference plane means attracts the electromagnetic field from the stimulator means to pass through and interact with said BUT; d) providing sensor detection means without electrical contact with said BUT wherein said sensor detection means detect said currents and charges induced on said electrically conductive paths, parts and surfaces, wherein said sensor detection means provide an output signal representative of the detected currents and charges, and wherein said sensor detection means is located adjacent to said at least one stimulator on said one side of said BUT and isolated from said at least one stimulator by insulation means; (e) providing positioning fixturing and movement means for said electromagnetic signal applying means, said sensor detection means and said BUT, wherein there is provided relative movement with respect to said BUT of said sensor detection means and said at least one stimulator for scanning said BUT to generate a series of the output signals which relates to at least a part of the BUT; (f) providing computer analysis of said series of output signals from said sensor detection means to detect defects in said BUT.