Definition

Functional test (FCT) verifies that an assembled PCB operates correctly by powering the board and testing its actual functionality, often simulating real-world operating conditions. Unlike ICT which tests individual components, functional test validates the complete system: firmware execution, communication interfaces, sensor responses, and output signals. Test fixtures connect to the board through production connectors or dedicated test points. For PCB designers, functional test affects: connector placement (accessible for fixture connection), test point provision (for probing internal signals), debug headers (UART, JTAG for diagnostics), and LED/indicator placement (for visual verification). Include test modes in firmware that exercise board functions systematically.