What is dielectric breakdown, Physics

Assignment Help:

What is dielectric breakdown? Explain briefly the various factors contributing to breakdowns in dielectrics.

Ans.: Electric Breakdown: When the electric field applied across any substance exceeds threshold breakdown field for that substance, the insulator suddenly turns into a resistor, Here a large usually abrupt rise in electric current is produced small increase in electric voltage. Breakdown can be intentional and controlled of accidental. Lightning is the most familiar example of breakdown.   

Electrical breakdown in Gas: In a gas, the potential gradient may become high enough to accelerate the naturally present may become high enough to accelerate the naturally present ions to such velocities that cause further ionization upon collision with other atoms. The process is corona discharge. If the region of ionization does not extend between oppositely charged electrodes, if the ionization region the gap between electrodes breaking down the insulation provided by the gas the process is ionization discharge. When controlled by the ballast of a fluorescent lamp the process converts electric power to light.  

Electrical Breakdown in Solid: In a solid, when the electric field gradient exceeds valence bonds between atoms are broken and current flows. Such a disruptive current heats the solid abruptly. During electrical breakdown, any free charge carrier being accelerated by the strong electric field will have enough velocity to knock electrons from any atom it strikes. Rapidly the insulator becomes filled with mobile carriers due to creation of more and more charge carriers and its resistance drops. In are the outbreak of conductivity is called corona discharge or a spark. 

Application: Electrical breakdown can be useful in every day applications such as spark plugs for gasoline engines, electrical welding of metals of for metal melting in an electric arc fumace.     

 

 


Related Discussions:- What is dielectric breakdown

Presbyopia, Presbyopia: The accommodation power of a person is lost by ...

Presbyopia: The accommodation power of a person is lost by which the suffers a long sightedness. It is known as Presbyopia or lack of accommodation.

Determine the gravitational force of attraction, Two steel balls are at a d...

Two steel balls are at a distance S from one another. As the mass of ONE of the balls is doubled, the gravitational force of attraction between them is: a) Quartered b) H

What is the way of the area element, The area element that seems in the in...

The area element that seems in the integral is a vector. Area like an amount of coverage would appear to be a scalar quantity. What is the way of the area element ?   Ans

Find the final temperature, A copper pot with mass 0.500 kg contains 0.170 ...

A copper pot with mass 0.500 kg contains 0.170 kg of water ata temperature of 20.0ºC. A 0.250-kg block of iron at85.0ºC is dropped into the pot. Find the final temperature, assumin

Why is the mass of a nucleus less than masses of neutron, Why is the mass o...

Why is the mass of a nucleus always less than the sum of the masses of its constituents, neutrons and protons? If the total number of neutrons and protons in a nuclear reaction

Heat, what is expansion of solids

what is expansion of solids

Evaluate the direction of the current in circuit, Q. Point out the directio...

Q. Point out the direction of the current if any induced to flow in the coil by the changing magnetic field. Answer: 1. Given: declining number of magnetic field line

Daltons law of partial pressures, Dalton's law of partial pressures (J. Dal...

Dalton's law of partial pressures (J. Dalton) The overall pressure of a mixture of ideal gases is equivalent to the total of the partial pressures of its components; i.e., the

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd