ICT and FCT are the two core electrical tests in electronics manufacturing. They answer different questions, and most production lines run both. Here's how they differ — and how VILOOK TECH builds the jigs and software for each.
What is ICT (In-Circuit Test)?
ICT verifies the manufacturing of a populated PCB at the component level. Using test points or a bed-of-nails fixture, it measures resistance, capacitance, diodes, shorts and opens to confirm each part is present, correctly placed and properly soldered. It is fast, high-coverage, and excellent at catching assembly defects early — before they become expensive.
What is FCT (Functional Circuit Test)?
FCT powers the board up and exercises it the way the finished product will be used — checking that inputs, outputs, signals and firmware behave to spec. Where ICT asks 'is it built correctly?', FCT asks 'does it actually work?'. FCT typically runs after ICT, closer to the end of the line.
ICT vs FCT: a quick comparison
ICT tests components and connections without powering the product's intended function; it is fast and catches build defects. FCT tests real behavior with power applied; it catches functional faults ICT cannot see. ICT fixtures need precise mechanical contact to many test points; FCT fixtures focus on connectors, interfaces and the operating environment. Used together, they give both manufacturing-quality and functional confidence.
Which one do you need?
If you are catching solder and placement defects at volume, you need ICT. If you must guarantee the product functions before it ships, you need FCT. High-reliability and high-volume lines almost always use both, often in sequence. The right answer depends on your product, defect profile and throughput — which is exactly what we scope with you.
How VILOOK TECH helps
VILOOK TECH designs and builds both ICT and FCT test jigs — in-line and manual — engineered to your specific PCB and line, and develops the custom test software that drives them, tuned to your line's standard and integrated with your measurement data. From PCB design to test fixtures to automation, it's one in-house engineering team.