1.4 Grounding and Measurements

Generally, ground is the voltage reference or zero point of a circuit. Ideally, everything connected to ground is also zero, with parasitic elements being negligible. On a Printed Circuit Board (PCB) with a solid and uninterrupted ground plane, the impedance from a ground point to any other point on the plane is very low.

However, this assumption may no longer be valid on a more complex design with interruptions in the ground plane or vias connecting a circuit on another layer to ground.