Ground

The term ‘ground’ is used as a general reference for ‘zero potential’: the point in an electrical circuit where there is no potential difference between the positive and negative terminals of the voltage source.

As a consequence of the lack of potential, ground is a point at which no current can be generated.

The term originates from domestic electrical systems where the circuit box is literally attached to the ground (represented by the green and yellow ribboned wires in plug sockets and light fixtures etc) where current is discharged to prevent appliances emitting electrical shocks.

In circuit diagrams with simple DC current, ground is taken to be the negative terminal of the voltage source.

The symbol for ground in circuit diagrams: