An in-circuit test is a test that makes sure there are no shorts, resistances or other problems with printed circuit boards (PCBs). It is intended to ensure proper manufacturing and quality in PCBs. The most common in-circuit test method is the bed-of-nails test, in which the PCB is pressed against a panel of connection pins so the pins can check for any electrical problems. There are press-down and vacuum-seal bed-of-nails testers, with vacuum generally considered better but also much more expensive. While this test can help manufacturers test for PCB problems, there are limitations, such as faulty master designs; contacts also cannot be quality tested.
Many electrical components need to work simultaneously and as a team to make a PCB function. During the manufacturing process, several problems can occur that would keep a PCB from functioning. The machines putting the PCB together may malfunction, or some of the smaller components may be faulty. To check for circuit functionality, an in-circuit test is performed.
