DETECTING ELECTRICAL SHORTS ON PRINTED-CIRCUIT BOARDS

Consider a printed circuit board with N signal paths in which k (not known a priori) paths are subjected to electrical shorts. A straight forward technique to detect all shorts is to test each pair of signal paths separately. This method needs (N2— N)/2 tests. In order to reduce the testing effort, manufacturers introduced a device that could test a group of signal paths against another group of signal paths. With the help of this device, a method with N + ((k2—k)/) tests needed was patented in 1982. In this paper, we present a new method that requires only O(k[log2N]) tests to achieve the same resolution using the same device. © 1990 Taylor & Francis Group, LLC.