InCircuitTests

InCircuitTests is a category of testing approaches used in electronics manufacturing to verify the electrical integrity of assembled printed circuit boards (PCBs) through in-circuit measurements. It aims to detect faults such as opens, shorts, incorrect component values, or misplaced devices that are not visible on inspection. ICT tests are typically executed in production lines using automated equipment and specially designed fixtures, with the results guiding repair or rejection decisions.

Methods and tools include Automated Test Equipment (ATE), bed-of-nails fixtures, boundary-scan (JTAG), and test software. Tests commonly performed are continuity and resistance checks, diode and transistor checks, capacitor leakage tests, and power-up checks. Boundary-scan enables testing of networks that lack direct access, increasing fault coverage on densely populated boards.

Applications and workflow: ICT is widely used in high-volume electronics manufacturing, providing high fault coverage with fast test cycles. It is often employed early in the post-assembly flow, before functional testing, and is complemented by automated optical inspection (AOI) and X-ray inspection to improve overall quality. Limitations include the high cost and time required to develop fixtures, as well as reduced effectiveness for boards with unusual components or nets that are difficult to access.

History and scope: ICT originated as a method to test populated boards and has evolved with advancements in boundary-scan techniques and modular fixtures, broadening its applicability across different product types and production scales. The term InCircuitTests is sometimes used by vendors as branding for ICT offerings or as a generic descriptor for this class of testing.

See also: In-circuit testing, boundary-scan, JTAG, functional testing, AOI, X-ray.