Definition: Ground is the context of circuit is the lowest reference voltage point often denoted as 0V.
In practice: Ground is referenced as the lowest impedance path for current return path.
- Ground in practical circuit is never 0V, it has voltage distribution at each point of the ground plane inside a PCB that is heavily dependent on circuit behavior.
- Ground is designed in PCB circuit as a large continuous plane of copper.
- DC current returns to the path of least resistance (i.e i.e widest and shortest path)
- AC current returns to the path of least impedance (i.e shortest current loop)