A closed insulating vessel containing a gas at low pressure through which an electric current flows when sufficient voltage is applied to its electrodes.
Any of various devices in which a gas or metal vapor inside sealed glass is used to conduct current when voltage is applied.
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.