Because of the fine, minuscule connections created on printed circuit boards (PCBs), there are numerous chances for errors to occur during the board's fabrication. Testing can be performed throughout the manufacturing process, however, which can reduce or eliminate potential errors. In complex circuits with hundreds or thousands of connections, such testing procedures can be a godsend.

Inspecting and Testing PCBs

The first round of testing for PCBs can come as early as the design stage. Many computer-aided design (CAD) programs include testing and environmental simulation features that enable a user to conduct "experiments" on a theoretical design. By applying a current to your design in the virtual realm, you can get a better sense of how the circuit will function once it is finally created in a hard copy.

Once the board has been created, it is important to check for several common errors. The first of these problems occurs when a circuit pathway has been inadvertently scraped off, rendering the circuit open and nonfunctional. This problem occurs when the etch resist hasn't sufficiently covered all of the pathways before the outer copper layer is etched off.

The opposite of this problem can also occur. That is, it is possible for a bridge to erroneously occur between sections that are meant to be isolated from another. The result of this bridge is a short circuit, which can either cause a nonfunctional or an overblown circuit. Testing procedures can measure the current and make sure that it is flowing in the proper way through the board.