For questions about ground loops, which occur when multiple ground nodes in a circuit (which should be at the same potential) actually have a potential difference between them. This is usually caused by a significant current flowing between the ground node(s), thus producing a voltage between them. Ground loops cause various problems in a circuit.

For questions about ground loops, which occur when multiple ground nodes in a circuit (which should be at the same potential) actually have a potential difference between them. This is usually caused by a significant current flowing between the ground node(s), thus producing a voltage between them. Ground loops cause various problems in a circuit.

See Wikipedia's article on ground loops for more information.