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

CRT, can electrons from an electron gun produce electricity

can electrons from an electron gun produce electricity

Create a ray diagram, A person is tasked with creating a ray diagram to con...

A person is tasked with creating a ray diagram to conclude the characteristics of the image of an object formed by a concave lens. The person has accurately drawn the principal axi

Explain a simple theodolite or astrolabe, A simple theodolite or astrolabe ...

A simple theodolite or astrolabe A simple theodolite or astrolabe is formed by fixing a drinking straw to the base line of a protractor with sealing wax or glue. A plumb line h

Quantam mechanics, what is the physical significance of Compton effect?

what is the physical significance of Compton effect?

Illustrate a labelled diagram of hertz experimental, Illustrate a labelled ...

Illustrate a labelled diagram of Hertz's experimental set-up to produce electromagnetic waves. Describe the generation of- electromagnetic waves using this set-up.

Diamond dosimetry, what is the working principle of diamond dosimeter and w...

what is the working principle of diamond dosimeter and whast are its advantages and disadvantages over other dosimeters?

What is the dynamic resistance, A coil of inductance 100 mH and resistance ...

A coil of inductance 100 mH and resistance 800Ω is connected in parallel with a variable capacitor across a 12V, 5kHz supply. Determine for the condition when the supply curre

What is the magnitude of the impulse acting on the ball, A ball with an ini...

A ball with an initial momentum of 6.00 kg.m/s bounces off a wall and travels in the opposite direction with a momentum of 4.00 kg.m/s. What is the magnitude of the impulse ac

What is described by millikan experiment?, The Millikan experiment showed t...

The Millikan experiment showed that electric charge was: a) Negative b) Quantized c) Positive d) Immeasurable Ans: The Millikan experiment showed that elec

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