discharge tube

noun Electronics.

1. gas tube.

noun

1. electronics an electrical device in which current flow is by electrons and ions in an ionized gas, as in a fluorescent light or neon tube

1. A closed vessel having electrodes at either end and containing a gas at low pressure. When a sufficient voltage is applied to the electrodes, an electric current flows through the gas. Discharge tubes can be used to prevent current flow below a certain voltage; they can also function as lamps by the use of ionizing gas, which glows when current flows through the tube.