Test Technologies

A test technique’s principle, optical or electric, is decisive for the possible adaptability in regard to fault detection. With an optical technology all visible faults can be found. These are, e.g. missing components, wrong components or even reverse polarised and distorted components. The possibility of a qualitative evaluation of solder joints according to the IPC norm (IPC-A-610) should be highlighted. The optical test principle faces its limits on the electric field. As a matter of course, one cannot make any statement about the correct functioning of a component. In respect to apply an optical test technology successfully, it is essential to have an unrestricted view at the board.
In contrast, the electric test is used to prove the correct functionality of a component, e.g. if a resistor really has 10 or if the output drivers of an IC are working correctly. Also, a free access to the PCB or single pin is not compulsory for each electric test technology. What cannot be executed with this principle is the appraisal of a solder joint as well as the detection of a component’s mechanical defect or the like.

What test technologies will emerge being most useful in the future? Or will combinations of test methodologies make most sense?