What is FCT Testing A Guide to Functional Circuit Testing in Electronics Manufacturing
                     WHAT IS FCT TESTING? A 
GUIDE TO FUNCTIONAL 
CIRCUIT TESTING IN 
ELECTRONICS 
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ABOUT US
Ever wonder how that smartphone in your 
pocket actually works the way it's supposed 
to? There's a whole world of testing behind 
the scenes that most people never think 
about. FCT testing might sound like tech 
jargon, but it's basically the final exam every 
electronic device takes before landing in your 
hands.
www.ewme.co
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THE BASICS OF 
FUNCTIONAL 
CIRCUIT 
TEsting
Think of FCT like a driving test for electronics. 
Sure, a car might look perfect sitting in the 
lot, but can it actually start, shift gears, and 
stop when you hit the brakes? That's exactly 
what functional circuit testing does for 
electronic products.
Unlike other testing methods that might check 
individual components, FCT looks at the big 
picture. Does the whole system work 
together? Can it handle real-world conditions? 
These are the questions that keep engineers 
up at night.
WHY FCT MATTERS 
MORE THAN YOU 
HTerHe's IthNe thKing about electronics manufactu
ring—mistakes are expensive. Really expensive. 
Finding a problem after products hit store shelves 
can cost companies millions. That's where 
functional testing becomes a lifesaver. But it's not 
just about money, safety plays a huge role too. 
Medical devices, automotive systems, aerospace 
equipment—these products can't afford to fail. 
FCT helps catch problems before they become 
disasters.
HOW FCT ACTUALLY 
WORKS
A custom test fixture holds the circuit board 
in place and connects to key test points, 
while software simulates real-world use to 
check functions, timing, and responses.
Throughout testing, precise measurements 
and pass/fail results are logged to detect 
issues, analyze trends, and improve 
manufacturing quality.
TYPES OF FCT TESTING 
METHODS
• In-circuit testing focuses on individual components while 
they're still part of the larger system. Think of it like checking 
each instrument in an orchestra while the whole band plays 
• tBooguentdhaerr.y scan testing uses special circuits built into modern 
chips. These circuits act like internal spies, reporting back on 
what's happening inside components that would otherwise be 
• iFmunpcotsiosinbalel  tteos tteinsgt. at the system level treats the entire product as a 
black box. Testers don't care how the magic happens inside—they 
just want to verify that inputs produce the expected outputs.
• Some companies use automated test equipment that can handle 
multiple boards simultaneously. These systems work around the clock, 
testing thousands of units per day with minimal human intervention.
COMMON 
CHALLENGES IN FCT 
GettIinMg tePst cLovEeraMge rEighNt prTeseAntsT a IcoOnstNant 
struggle. Too little testing and defects slip 
through. Too much testing and production slows to 
a crawl. Finding that sweet spot requires 
experience and careful planning. Test fixture 
design can make or break an FCT program. Poorly 
designed fixtures cause false failures, damaged 
boards, and frustrated operators. Good fixtures 
last for years and provide consistent results.
SETTING UP AN 
EFFECTIVE FCT 
PROGRAM
Start with clear requirements to focus testing on critical 
functions, while identifying secondary features that add 
value. Involve design engineers early, as their deep circuit 
knowledge helps define optimal test points and methods. 
Ensure operators are well trained so test equipment is used 
correctly and consistently, and update training as 
technologies change. Plan for maintenance from the start by 
scheduling regular calibration, keeping spare parts 
available, and documenting procedures to reduce downtime 
and maintain reliable testing performance.
CONTACT US
Phone
512-258-2303
Email
[email protected]
Website
www.ewme.com
Location
1974 Steam Way, Round Rock, Texas 
78665
THANK 
YOU