In-Circuit Test (ICT) is a standard test method to check manufacturing defects and defective components by testing the electrical properties and electrical connections of online components. It mainly checks the open and short-circuit conditions of single components and circuit networks online, and is characterized by simple operation, quick and rapid, and accurate fault location.
Needle bed online test can be analog device function and digital device logic function test, fault coverage is high, but for each single board must make a special needle bed fixture, fixture production and program development cycle is long.
Flying probe on-line test basically only static test, the advantage is that there is no need to make fixtures, program development time is short.
1. The scope of ICT
Online testing to check the electrical performance of online components on the manufactured board and the connection of the circuit network, able to quantitatively measure resistors, capacitors, inductors, crystals and other devices; diodes, transistors, optocouplers, transformers, relays, operational amplifiers, power supply modules, etc., functional testing; functional testing of small and medium-sized integrated circuits, such as all the 74 series, Memory class, Commonly used driver class and switching class and other ICs.
It finds out the defects of manufacturing process and defective components by directly testing the electrical performance of on-line components. Component class can check out the component value of the super poor, failure or damage; Memory class can check out the program, etc.; on the process class can be found, such as solder short circuit, component insertion error, insertion of the reverse, leakage of the installation, pin warping, false soldering, PCB short-circuit, disconnection and other faults.
ICT features
2. The fault of the test is directly localized in the specific components, component pins, network points, fault location is accurate. The maintenance of the fault without more specialized knowledge. It uses program-controlled automatic testing, simple operation, fast and rapid testing, single-board test time is generally only a few seconds to tens of seconds.
The significance of ICT
3. Online test is usually the first test process in production, can reflect the manufacturing situation in a timely manner, is conducive to the improvement and enhancement of the process. ICT tested fault board, due to fault localization is accurate, easy to repair, can significantly improve production efficiency and reduce maintenance costs. Because of its specific test items, it is one of the important test means for modern mass production quality assurance.
