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58 DESIGN007 MAGAZINE I AUGUST 2020 The Nuts and Bolts of Electrical Testing Electrical testing verifies connections and paths in a PCB to ensure that current is mov- ing in the proper way between components. Whether you're a beginning PCB designer or a grizzled veteran, electrical testing is an impor- tant step in PCB manufacturing. Without it, you might just end up with a useless chunk of substrate and copper. In this column, we'll explore the world of electrical testing. We will examine a variety of testing methods, what options to look for in a PCB manufacturer, and how to ensure that you're getting the best value out of the electri- cal testing options available to you. The Lingo of Electric Testing Like everything else in the world of electron- ics, electrical testing has its own vocabulary. Before beginning our exploration, let's get a handle on the jargon. Net A net is, to put it simply, a circuit. Your CAD tool can output a specially formatted list of nets or circuits in your project known as a netlist. This is required for certain manufacturers. Opens and Shorts An open is a break in a net or circuit, while a short is as you would expect—an undesired connection in a net or circuit. Bed of Nails Also known as a clamshell or universal grid test, the bed of nails testing method uses spring- loaded, fixed contacts to test circuits on a PCB. This method is best for high-volume produc- tion, where a lot of speed is needed in testing. Flying Probe A flying probe test uses software-configured movable contacts to test circuits on a board Connect the Dots by Bob Tise and Matt Stevenson, SUNSTONE CIRCUITS