How PCBs are electrically tested

Printedcircuit boards need to be electrically tested according to the IPC-9252Electrical Test Guidelines and Requirements for Unloaded Printed CircuitBoards. But how exactly are these boards tested?

Typesof PCB electrical testing

Electricaltesting of PCBs does not require specific tests, as long as any tests performedprove that the board meets the electrical test criteria. Electrical testingprocedures for printed circuit boards can include.

Capacitancetest: This is a test that looks for short circuits on the board. The procedureinvolves charging the network and then measuring the inductive capacity.

Resistancetesting: This type of test measures resistance in ohms. Resistance is a measureof the collisions that occur between electrons and atoms, which interfere withthe flow of electrons when current flows through a conductor. When testingresistance, you are looking for low resistance as an indicator of a goodconductor. The longer and thinner the circuit, the higher the resistance, sothis is a factor you must consider when testing.

ComparisonTest: This is done using a standard motherboard that you have verified to teachthe netlist program and then you compare other motherboards to thatmotherboard. The problem with this type of testing is that there is always thepossibility that the motherboard may have initial defects.

ContinuityTest: This test ensures that the resistance between test points does not exceedthe required limits.

FlipTest: The test is performed on either side of the board as a generic grid. Itis much more accurate than the flip-flop method below.

Flip-FlopTest: Both sides of the board are tested simultaneously in one pass. Thismethod is a popular reliability method because you are testing all points onthe board at the same time.

Adjacencytesting: Short circuit testing is performed by checking the isolation betweenconductors. You can test for adjacent adjacencies or line-of-sight adjacencies.

Adjacencytest: This test checks the isolation between conductors.

Flyingprobe test: This very reliable test method involves the use of a flying probetest sequence, which probes the board at high speed, looking for shorts andopenings throughout the board.