Virtual ground
From Academic Kids
Virtual ground is a concept found in electrical circuit designs. It identifies a point in an electric circuit as being held close to the ground level electric potential. This happens due to the actions or effects of the parts in the circuit. It is called virtual since this point does not have any real electrical connection to ground.
A typical example for a virtual ground point is found in circuits using operational amplifiers with negative feedback.
Three-phase electrical "Y" circuits are said to have a virtual ground node when their sources and loads are balanced respectively.
