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

Can you give the s.i unit of electric displacement vector, Can you give the...

Can you give the S.I unit of electric displacement vector?

Factors affecting velocity of sound in gaseous medium, Factors which are af...

Factors which are affect velocity of sound in gaseous medium is (1) Effect of density (2) Effect of pressure (3) Effect of temperature :      (4) Effect of humidity

Why is it that the frequency of light remains the constant., Why is it that...

Why is it that the frequency of light remains the constant as it undergoes refraction at the interface of two material mediums? Ans) If frequencies are dissimilar in different m

What is meant by doping, Q. What is meant by doping? The process of ad...

Q. What is meant by doping? The process of addition of extremely small amount of impurity into an intrinsic semiconductor is called doping.

Ultrasonic, how faster ultrsonic waves will travel in solids.

how faster ultrsonic waves will travel in solids.

State biot-savart law, State Biot-Savart's law. Using this law, derive the...

State Biot-Savart's law. Using this law, derive the expression for the magnetic field because of a current carrying circular loop of radius 'R', at a point which is at a distance '

Find leakage resistance, A set of open circuit test and short circuit test ...

A set of open circuit test and short circuit test have been performed on a transformer. A supply voltage of 480 V is applied to the primary side of the transformer and the followin

Electrostatic, Why we are showing work done over a closed path is zero to ...

Why we are showing work done over a closed path is zero to prove that electrostatic forces are conservative

Electric fire of resistance - electric current, A current of 12A flows in t...

A current of 12A flows in the element of an electric fire of resistance 25?. Verify the power dissipated by the element. If the ?re is on for 5 hours every day, measure for a

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