A Low-Cost Printed Circuit Board to Perform Functional and In-Circuit Testing

In-circuit testing (ICT) and functional testing (FCT) are diagnostic methods used to assess the operational integrity of discrete electronic components and circuitry on a Printed Cir-cuit Board (PCB). Commercial electrical testing systems are usually modular, consisting of multiple control and processing circuit boards, which makes them highly specialized and expensive. This creates a significant accessibility challenge, especially for small and me-dium-sized industries. In this study, a low-cost device board was developed to perform in-circuit and functional testing based on fundamental principles of electrical testing. The design incorporates relay banks to connect electrical test node probes with the Device Un-der Test (DUT), enabling resistance and capacitance measurements, shorts and open-circuit detection, voltage stimuli, digital multimeter readings, analog signal condi-tioning and amplification, general-purpose input/output, receive/transmit data, among other functions. These operations are managed via RS-232, opto-isolated UART ports, Ethernet TCP/IP, and digital input/output (I/O) control ports. Prototypes were built and tested in automated functional test setups to verify their performance and proper opera-tion. The results show that a single, low-cost PCB can effectively carry out testing tasks typically performed by expensive commercial systems, providing a versatile and econom-ical alternative tool for electrical testing for prototyping, and end-of-line test equipment.