Contact Probe Array

A critical component within an Electrical Test Fixture, the Contact Probe Array consists of multiple individual spring-loaded probes arranged in a specific pattern that matches the test points on the device under test (DUT). Its primary role is to provide reliable, repeatable, and low-resistance electrical connections between the test system's instrumentation (e.g., a bed-of-nails tester, flying probe, or in-circuit tester) and the DUT's pads, pins, or vias. This enables the execution of functional tests, continuity checks, in-circuit tests (ICT), and boundary-scan tests. The array's design is customized for each specific PCB or component layout to ensure accurate alignment and contact pressure.

Each probe in the array is a spring-loaded pogo pin. When the test fixture is actuated (e.g., a vacuum or pneumatic press lowers the fixture plate), the array is pressed onto the DUT. The probes compress, their internal springs ensuring consistent contact force. The probe tip (often a sharp or crowned point) makes physical and electrical contact with the test point, while the probe body connects to a wire or trace leading to the test system. This creates a temporary circuit path for applying test signals and measuring responses. After testing, the fixture retracts, and the springs return the probes to their extended position.