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

Electric spark, explain me about resistor in series

explain me about resistor in series

Spontaneity of a chemical reaction, How could you predict the spontaneity o...

How could you predict the spontaneity of a chemical reaction, given changes in entropy and enthalpy?

Explain electric potential, Electric Potential: Electric Potential veri...

Electric Potential: Electric Potential verifies the flow of charge. Its unit is volt, represented as "v".

Give an example of the elapse time for different observers, Two observers, ...

Two observers, A on earth and B in a spacecraft whose speed is 2.00 x 108 m/s, both set their watches to the same time when the ship is abreast of the earth. (a) How much tim

State about the term- voltage gain, Determine voltage gain for the circuit...

Determine voltage gain for the circuit shown in figure below, with R F = 100K ? and R 1 =10 K?   Ans. Determination of voltage gain: The provided operational

Determine the magnitude of the pointing vector, A laser beam from 200 watt ...

A laser beam from 200 watt source is focused on an area of 10 -8 m 2 . Determine the magnitude of the Pointing vector of the area.

Define potential difference, In an electric field difference among potentia...

In an electric field difference among potential energy of two points A and B is described as equal to the amount of work done (by external agent) in moving a unit positive charge f

Distinguish between interference and diffraction fringes, Q. Distinguish be...

Q. Distinguish between interference and diffraction fringes? Interference Diffraction 1) It is because of the superposition of secon

rectilinear scanner, Nuclear medicine imagining devices : Imagining ,or p...

Nuclear medicine imagining devices : Imagining ,or producing pictures of the distribution of the radioactivity is the most important aspect of nuclear medicine. Rectilinear s

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