Yes it can. A simple example would be where you connect the +ve pole of an AA cell to ground. Its -ve connection will then be at a potential of -1.5V relative to ground.So I know a voltage can be negative with respect to another relatively higher voltage, but can a voltage ever be lower than or negative with respect to earth ground (0 volts).
by Duane Benson
by Duane Benson
by Jake Hertz