is an unwanted oscillation
of a voltage
. It is caused when an electrical pulse causes the parasitic capacitances
in the circuit (i.e. those that are not part of the design, but just by-products of the materials used to construct the circuit) to resonate
at their characteristic frequency
. Ringing artifacts are also present in square waves.
Ringing is undesirable because it causes extra current to flow, thereby wasting energy and causing extra heating of the components; it can cause unwanted electromagnetic radiation to be emitted; and it may cause unwanted triggering of bistable elements in digital circuits.