In electronics and electrical engineering, a ground plane is a conductive surface referenced to zero volts. While the term “ground” is frequently accompanied by adjectives like “computer ground” or “signal ground,” these adjectives can create confusion and will be avoided. Instead, a ground plane is simply defined as a conductive surface referenced to zero volts.
The Earth itself is an electrical conductor, and connections to Earth are essential for lightning protection and electrical safety. Despite not being flat, the Earth is considered a form of a ground plane. However, a ground plane in electronic systems may or may not be physically connected to the Earth. For example, in aircraft, the framework might be a ground plane without a connection to Earth. In a facility built on a lava bed, where lava is an insulator, the building steel might still be considered ground.
Difference between a Ground plane and the actual Earth.
Electronic systems often feature multiple reference conductors, each serving a specific purpose. Some reference conductors may be earthed, and connected to Earth, while others are defined by the circuit itself. Regardless, the key concept is to have a conductive surface in the circuit considered at a zero reference potential. The idealized ground plane, as described, is a source of positive or negative charge, capable of supplying any amount of charge without requiring work to move charges along its surface. This ideal ground plane is an equipotential surface, simplifying the analysis of electronic circuits by providing a consistent reference point at zero potential.