Ringing
In
electrical circuits,
ringing is an unwanted
oscillation of a
voltage or
current. It is caused when an electrical pulse causes the parasitic
capacitances and
inductances 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.