There are various conditions that can cause muscle twitching. Minor muscle twitching is usually the result of less serious, lifestyle-related causes. More severe muscle twitching, however, is often the result of a serious condition.
An electrode is an electrical conductor used to make contact with a nonmetallic part of a circuit (e.g. a semiconductor, an electrolyte, a vacuum or air).
Inert electrode: An electrode that serves only as a source or sink for electrons without playing a chemical role in the electrode reaction. Noble metals, mercury, and carbon are typically used as inert electrodes. See for example the redox electrode.