METHOD AND APPARATUS FOR STRAIN MONITORING OF PRINTED CIRCUIT BOARD ASSEMBLIES

摘要

A technique of monitoring strain on a printed circuit board assembly involves the use of a strain detector (20) mounted on a printed circuit board (24). The strain detector is formed of a non-ductile material. The strain detector has a narrowed portion (70) forming a weak link that has a characteristic of breaking when a critical strain limit is exceeded. The method of monitoring can include visual or electrical inspection. The electrical inspection can include having a strain monitoring device (92). The strain monitoring device has a timer (94) connected to at least one strain detector and a memory (96) for storing results connected to the timer. The capacitance of at least one of the strain detectors is sampled and any change in capacitance is recorded to the memory. In one embodiment, a time stamp occurs in the memory based on when an electrical property changes across at least one of the strain detectors.