What is In-Circuit Testing (ICT)?

Testing can be performed through different methods. One of the most common is ICT (In-Circuit Testing). ICT is a reliable, fully automated, high-volume testing. It checks individual components on the board for any imperfections.

PCBs are complex devices with multiple components. They are assembled using thousands of connections. Even a minor defect in the assembly could affect the overall quality and performance. Thus, PCBs need to undergo accurate and comprehensive testing. This will avoid costly repairs and recalls.

How does ICT work?

ICT uses an electrical probe to test components at individual points. ICT checks for short circuits, opens, resistance, capacitance, and other parameters. The test will flag any discrepancies. In-Circuit Tests are usually conducted in two parts: with power off and power on.

There are several different types of ICT available on the market. They vary in performance, capability and procedure. Three main elements are common to all testers:

• It tells the system what tests to perform and how to perform them. The software also details the pass and fail criteria.
• In-circuit tester. A matrix of drivers and sensors used to set up and perform the testing.
• It acts as a physical interface between the board and the in-circuit tester. It can use a “bed of nails” fixture.

What defects does ICT identify?

ICT verifies each component on a PCB, one by one. Provided accessibility to all the nodes on the board, ICT can locate about 98% of faults. ICT tests the following:

• Short circuits
• Solder bridges
• Wrong or missing components
• Component spacing and size
• Shorts between traces and/or component leads
• Opens (open circuits) where there should be electrical continuity
• Resistor Values
• Jumpers/switches in correct location
• Presence or absence of passive/active components
• Capacitance and inductance values

What are the advantages of ICT testing?

ICT is a popular testing system, thanks to its ease of use, speed and accuracy. Its main advantages are:

• Easy to program and operate.
• Fully automated. Leaves little room for operator error.
• Speed (about 1-2 minutes per assembly). This makes it ideal for mass testing.
• High reliability.
• Covers a wide range of potential faults.
• Test results are easy to understand.
• Requires minimal maintenance costs.

What are the disadvantages of ICT testing?

ICT it’s not, of course, a perfect testing system. It has some drawbacks:

• Test fixtures are expensive to develop.
• It doesn’t detect multi power connections missing, redundant power connections, decoupling capacitors missing and mechanical fixings.
• Test pins need to make proper surface contact. Otherwise, results will be inconsistent.
• Test pins need regular cleaning and replacing to prevent failure and false positives.

Conro Electronics is a leading supplier of materials and tools in the electronic manufacturing industry.

We’ll show you how to improve product reliability while increasing performance and lowering costs. Our team of technical support specialists will provide your company with dependable global supply, unrivalled efficiency, and superior technical support.

Feel free to contact us on 0208 953 1211 or send us an email to info@conro.com