IPC - Association Connecting Electronics Industries
Scope
A nondestructive inspection method for determining the quality of plated-through connections in printed wiring boards. 1.2 Theory. Copper will display a resistivity of known value depending upon the geometry of the shell and the conductivity of the copper. If the shell is not uniform@ defects such as cracks@ voids@ or thin spots in the copper will cause the measured resistance to be higher than the theoretical value. This value is computed by using the equation given in Fig. 1.