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

Force operating on and acceleration of the block, A block of mass m is rest...

A block of mass m is resting on a piece of smooth paper. The block has coefficient of static and kinetic friction μ s , μ k with the paper, correspondingly. You jerk the paper hor

Plane and convex mirrors, (a) You have studied that plane and convex mirror...

(a) You have studied that plane and convex mirrors produce virtual images of objects. Can they generate real image under some circumstances? Explain. (b) A virtual image we a

Triode valve, What do you mean by amplification factor of a triode valve

What do you mean by amplification factor of a triode valve

Explain coulumb''s law, Coulumb's Law: Statement: The magnitude of t...

Coulumb's Law: Statement: The magnitude of the electrostatic force among two point's charges is directly proportional to the product of the magnitude of the charges and inve

Right-hand palm rule, Stretch the fingers and thumb of right hand at right ...

Stretch the fingers and thumb of right hand at right angles to one another. Then if the fingers shows in the direction of field and thumb in the direction of current i, then normal

Thermometers, what are advantages and disadvantages for the six''s thermome...

what are advantages and disadvantages for the six''s thermometer

Define primary cell, Primary cell Is that cell in which electrical energy i...

Primary cell Is that cell in which electrical energy is produced because of chemical energy. In the primary cell, chemical reaction is irreversible. This cell cannot be recharged.

Light, diffenrence between pure and impure spectrum.

diffenrence between pure and impure spectrum.

What point does the beam converge, Q. A beam of light converges at a point ...

Q. A beam of light converges at a point P. Now a lens is placed in the path of the convergent beam 12 cm from P. At what point does the beam converge if the lens is (a)a convex len

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