Off Pedestal Knowing how to measure PCB trace impedances can help you optimize circuit performance from DC to gigahertz. The ideal conductor is history. If you don't believe it, your designs could be toast. From DC to the gigahertz frequency ranges, PCB trace resistance and reactance can degrade product performance. Taking care to measure trace impedances accurately can help you determine why a circuit fails to perform optimally.
Problems begin with direct-current measurements.
For DC measurements, you needn't be concerned with reactance, but even the low levels of resistance that PCB traces exhibit can introduce errors. That trace exhibits about 0.18-W resistance. You can make a stab at measuring resistances of that magnitude using a standard DMM on its lowest resistance range. R L constitutes a low-resistance link from the ends of R B and R D opposite the galvanometer. SW L closed.