Acid test

摘要

You can expect a few in-warranty failures in any com-plex product. However, when there's a sudden increase j of such claims after the release of a new product, alarm bells should ring, and the design-engineering department should be involved. Such was the case in my company with a UV (ultraviolet)-light source and sensor assembly we were using to detect counterfeit currency, j Counterfeits sometimes fluoresce when you expose them to UV light, whereas genuine US currency usually does not.