Original Publication Date: 1987-May-01
Included in the Prior Art Database: 2005-Feb-01
Multilayered printed circuit cards and boards that are fabricated from glass cloth impregnated with epoxy resin are subjected to dielectric loss measurements. The measurements are used as an indicator of moisture in the various layers of the cards or boards. The magnitude of the capacitance and dielectric loss is measured between signal lines and adjacent power planes throughout the board. These measurements are typically made on an individual basis using a double pair of coaxial cables which are connected to the two plated through holes (PTHs) leading to the respective signal line to power plane being studied, and is connected to an instrument to measure dielectric loss and capacitance.