The most common dielectric gas is air, due to its ubiquity and low cost.

Dried and pressurized, as a dielectric gas for high-voltage equipment.

Dielectric gases can also serve as coolants.

It is investigated as a possible replacement for sulfur hexafluoride as a dielectric gas.

A dielectric gas, or insulating gas, is a dielectric material in gaseous state.

A rounded terminal minimizes the electric field around it, allowing greater potentials to be achieved without ionization of the surrounding air, or other dielectric gas.

More modern Van de Graaff generators are insulated by pressurized dielectric gas, usually freon or sulfur hexafluoride.

The dielectric gas may be pressurized, or a liquid dielectric (e.g. mineral oil) may be substituted to further extend the operating voltage.

It may operate in open air, it may be sealed, or it may be filled with a dielectric gas other than air or a liquid dielectric.

Insulation of the high voltages produced is often accomplished by immersing the Marx generator in transformer oil or a high pressure dielectric gas such as sulfur hexafluoride (SF).

Gas or liquid measurement applications include dry air, hydrocarbon processing, pure semiconductor gases, bulk pure gases, dielectric gases such as those in transformers and power plants, and natural gas pipeline transport.

Dielectric gases are used as electrical insulators in high voltage applications, e.g. transformers, circuit breakers (namely sulfur hexafluoride circuit breakers), switchgear (namely high voltage switchgear), radar waveguides, etc.

A good dielectric gas should have high dielectric strength, high thermal stability and chemical inertness against the construction materials used, non-flammability and low toxicity, low boiling point, good heat transfer properties, and low cost.

High voltage circuit breakers often use a blast of high pressure air, a special dielectric gas (such as SF under pressure), or immersion in mineral oil to quench the arc when the high voltage circuit is broken.

For this case, plasma is generated when an electrical current is applied across a dielectric gas or fluid (an electrically non-conducting material) as can be seen in the image below, which shows a discharge tube as a simple example (DC used for simplicity).

It is used as a fire suppression agent, a foaming agent, a highly effective refrigerant, a heat transfer medium, a dielectric gas, a sterilant carrier, a polymerization medium, a carrier fluid, a displacement drying agent, a thermodynamic power cycle working fluid, etc.