A ground is a direct electrical connection to the earth, a
connection to a particular point in an electrical or electronic
circuit, or an indirect connection that operates as the result
of capacitance between wireless equipment and the earth or a
large mass of conductive material. Electrical grounding is
important because it provides a reference voltage level (called
zero potential or ground potential) against which all other
voltages in a system are established and measured. An effective
electrical ground connection also minimizes the susceptibility
of equipment to interference, reduces the risk of equipment
damage due to lightning, eliminates electrostatic buildup that
can damage system components, and helps protect personnel who
service and repair electrical, electronic, and computer systems.
In effect, an electrical ground drains away any unwanted buildup
of electrical charge. When a point is connected to a good
ground, that point tends to stay at a constant voltage,
regardless of what happens elsewhere i