Printed Circuit Board Fault Inspection Based on Eddy Current Testing Using Planar Coil Sensor

This paper presents a printed circuit board (PCB) fault inspection method using eddy current testing generated from Helmholtz coils with a planar array-coil sensor to locate and inspect short and open faults on uniformly spaced interconnect single layer PCBs. The differences between the induced voltages from fault-free boards and faulty boards will be recorded in tables and translated into contour plots. The experimental results showed that in the presence of a short fault, the differences between the induced voltages from fault-free and faulty boards are highly negative. However, in the presence of an open fault, the differences between the induced voltages from fault free and faulty boards are highly positive. These highly positive or negative induced voltages can be translated into high density color regions on contour plots. The potential fault positions can be located by observing the color regions of the contour plots with respect to each element of the matrix sensor.