Abstract: A method and apparatus are disclosed for testing unpopulated and inactive populated printed circuit boards for manufacturing defects. The method and apparatus do not require electrical contact with the board under test. The method and apparatus include an AC source, which is connected to the stimulator(s). The stimulator(s) radiate an electromagnetic field onto the traces and components on the board under test and this interaction establishes a potential gradient along the traces and components. A sensor array is located adjacent to a stimulator (if only one is used) or between a pair of stimulators (if a dual arrangement is used) and detects the displacement currents flowing from the board under test. The sensors and stimulator(s) do not electrically connect to the board under test, which is positioned between a ground reference plane and a sensor/stimulator unit. By scanning across the entire surface of the board under test, a displacement current signature of the board under test is obtained.

Abstract: This application describes a method of testing for manufacturing faults and quality of unpopulated or inactive populated electronic printed circuit boards (PCB). This method can be used to develop a new contactless test system (CTS). An electromagnetic field is generated by an energizing plate connected to an AC signal. When a board under test (BUT) is placed within the electromagnetic field, perturbation of the original field by conducting elements on the BUT is solely a function of the geometrical layout of the conducting elements on the BUT. Therefore, measurement of the perturbed electromagnetic field produces a characteristic pattern for the BUT. Such a pattern can then be compared to a known pattern for the same type of board to determine whether the BUT is faulty (shorts or opens) or not faulty. The most distinctive feature of this method is that testing PCBs by this method requires no electrical contact with the BUT due to the use of the energizing plate.

Abstract: This application describes a novel method and its implementation for testing unpopulated and populated electronic printed circuit boards (PCBs). This method can be used to develop a new contactless test system (CTS). While eliminating drawbacks of existing test systems, this method measures electromagnetic near field distribution in the vicinity of a PCB, contactlessly, by using suitable sensors (possibly printed near field planar antennas) and sensitive measuring and processing devices. The electromagnetic fields (EMF) are generated by the distribution of charges and currents on paths and elements of the board under test (BUT). Therefore, accurate and repeatable measurements of these fields produce a specific pattern for the BUT. Such a pattern is then compared to a known pattern for the same type of board to determine whether the BUT is faulty or nonfaulty.