How does electric discharge takes place through gas?

Electric discharge in gases occurs when electric current flows through a gaseous medium due to ionization of the gas. The properties of electric discharges in gases are studied in connection with design of lighting sources and in the design of high voltage electrical equipment.

Why does electric discharge through a gas take place at low pressure?

Actually electric discharge takes place at low pressure because a small electric field is required. We know that at high altitude, pressure is very low with respect to low altitude for some electric field set – up in the atmosphere, the electron discharge takes place at high altitude but not at low.

What are gas pressures?

Gas pressure is the name given to the force exerted by gas particles colliding with the wall of their container. Pressure is force exerted over an area. Gas pressure is the force exerted by a gas on a specific area.

What happens when electric current is passed through a gas at low pressure?

When an electric current is passed through a gas, the gas emits light. This emission is exploited in many electric lamps. When a voltage is applied to the two electrodes and the pressure of the gas in the tube is reduced, eventually a pressure is reached at which a current flows, and the gas begins to glow.

How the pressure of gases in the discharge tube can be adjusted?

pressure is directly proportional to the number of molecules that is pressure depends on the amount of gas..so pressure can be altered by increasing or decreasing the amount of molecules..by evacuating , the pressure can be decreased and can be adjusted to the required value.

What is meant by gas discharge?

noun. A flow of electricity through a gas, typically accompanied by emission of light; a body of gas in which this is occurring.

Why does the gas in a gas discharge tube need to be at low pressure in order for the gas to emit light when an electric current is passed through the tube?

You need the low pressure in the tube so that the passage of the beam of electrons is not impeded very much by collision with air molecules. You need a reasonably high accelerating voltage to give the electrons enough kinetic energy to make the fluorescent screen glow when the electrons hit the screen.

Why the electrical discharge through the gases could be observed only at very low pressure and at very high voltage?

1)It can only be observed so because air is a poor conductor and on such harsh conditions(high voltage and low pressure) air conducts electricity.

How do gases apply pressure?

The pressure exerted by a gas is due to the random motion of particles in the gas. Gases have weak intermolecular forces and the particles are in continuous random motion and these particles collide with the walls of the container. These collisions with the walls of the container exert pressure on the gas.

What determines the pressure of a gas?

Overview. The pressure of an enclosed gas is dependent on the number of gas particles, the volume of the container, and the temperature of the gas. Increasing the number of gas particles in a container will increase the pressure. Increasing the volume of a container will increase the pressure.

Why is conduction easier in gases if the pressure is low will the conduction continue to improve if the pressure is made as low as nearly zero?

Answer : Conduction happens when an electron with enough kinetic energy collides with the electron of gas atoms. Whereas at low pressure due to an increase in their mean free path they are able to gain enough kinetic energy for ionization process so conduction is easier.

What is the pressure in discharge tube?

—The increase in pressure of a gas in a discharge tube due to the discharge has been measured for pressures from about 0.1 to 20 mm of mercury for helium, hydrogen, oxygen, nitrogen, air, carbon monoxide and carbon dioxide.

What is the purpose of electrical discharge?

An electrical discharge results from the creation of a conducting path between two points of different electrical potential in the medium in which the points are immersed. If the supply of electrical charge is continuous, the discharge is permanent, but otherwise it is temporary, and serves to equalize the potentials.

Do different gases have different breakdown voltage?

It is observed that different gases has different breakdown voltage under the same experimental conditions and electrode geometry. Besides, the breakdown voltage versus pressure curves of gaseous dielectrics follows the classic Paschen’s Law as well.

What is the potential difference between a gas and a medium?

Usually, the medium is a gas, often the atmosphere, and the potential difference is a large one, from a few hundred volts to millions of volts. If the two points are separated by a vacuum, there can be no discharge.

What is 86 high voltage electric discharge consolidation?

High voltage electric discharge consolidation belongs to the category of the electric pulse consolidation techniques. 86 HVEDC relies on the passage of a single pulse of current with duration in the order of one millisecond through a powder compact within a die, leading to a sudden energy release and densification ( Fig. 2 ).