What is PCB Electrical Testing?
Electrical testing is a critical inspection process in the PCB manufacturing workflow, primarily used to identify electrical issues such as open circuits, short circuits, and miswiring. Its core purpose is to ensure that every circuit connection meets the designed electrical specifications, thereby providing reliable assurance for subsequent SMT assembly and product usage.
PCB electrical testing generally refers to continuity testing of bare boards, and flying probe testing is considered one method within this category. However, in industry practice, Flying probe testing and traditional electrical testing are often distinguished: flying probe testing is suitable for prototype runs and small batch orders, offering high flexibility and no need for dedicated test fixtures; whereas “electrical testing” in a narrower sense usually refers to large-scale testing using a bed-of-nails fixture. This fixture consists of hundreds or thousands of densely arranged spring-loaded pins that simultaneously contact all test points on the PCB, enabling one-step, parallel full-board testing with very high efficiency, ideal for medium to large volume production.
The basic principle involves detecting circuit continuity based on electrical current or voltage responses. Test equipment applies signals to two or more designated test points and measures changes in resistance, voltage, or current to determine whether circuits are properly connected or if faults such as shorts or cold solder joints exist. The measured data is then compared against the original design netlist to verify the accuracy of circuit connections.
Leveraging advanced modern test equipment, electrical testing achieves micron-level positioning accuracy, high testing efficiency, and excellent reliability. It quickly and accurately detects common electrical defects including opens, shorts, cold solder joints, and miswiring. As a vital part of PCB quality control, electrical testing plays an indispensable role in ensuring the quality of finished circuit boards and improving the yield of subsequent assembly processes.