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

Second law of black hole dynamics, Second law of black hole dynamics ...

Second law of black hole dynamics Along with black-hole interactions, or interactions among normal matter and black holes, the total of the surface areas of all black holes i

Define step - up transformer, A transformer has 124 turns on the  primary c...

A transformer has 124 turns on the  primary coil and 18,600 turns on the  secondary coil. a. Is this a step-down or a step-up  transformer? step-up transformer

Find the minimum angle at which a roadbed should be banked, Find the minimu...

Find the minimum angle at which a roadbed should be banked Determine the minimum angle at which a roadbed should be banked so that a car traveling at 20.0 m/s can safely negotia

First law of thermodynamics for a closed system, Illustrate the first law o...

Illustrate the first law of thermodynamics for a closed system undergoing cyclic process.

Wave optics, A ray of light falls on a glass slab of refractive index u.if ...

A ray of light falls on a glass slab of refractive index u.if the reflected and refracted rays are mutually perpendicular to each other,find the angle of incidence. Ans) let i b

Zero gravity, what will happen if gravity becomes zero?is it possible in ea...

what will happen if gravity becomes zero?is it possible in earth?

Emf and size, is there relation between emf and size os cell?

is there relation between emf and size os cell?

Specific heat, A 3Kg bar of aluminum has to be heated from 25 degrees Cels...

A 3Kg bar of aluminum has to be heated from 25 degrees Celsius to 75 degrees Celsius. how many calories are needed to achieve this temperature increase?

Potential barrier, Potential barrier One either side of the junction, t...

Potential barrier One either side of the junction, the region ‘D' becomes free from mobile charge carriers. That is on n-type side of D, no free electrons exist and on p-type s

Define angle of repose, Define angle of repose Consider a body resting ...

Define angle of repose Consider a body resting on a plane OA. Assume this plane OA is slowly raised from the horizontal position to incline it with the horizontal.

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