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

Rectifier, junction diode as a half wave rectifier

junction diode as a half wave rectifier

International system of units, The coherent & rationalized system of units,...

The coherent & rationalized system of units, derived through the m.k.s. system (that itself is derived from the metric system) in common employ in physics today.

Sound, explain the pitch of sound and also explain is the ghosts come in th...

explain the pitch of sound and also explain is the ghosts come in the category of matter? is the sound is the form of wave? explain sound,intensity,types,loudness of sound, quality

Explain the applications of polarization of light, Explain the applications...

Explain the applications of polarization of light?  Write any four applications of interference of light. Illustrate how plane polarized light obtained by reflection.

Define eddy currents, Define Eddy Currents ? If you try to pull a solid ...

Define Eddy Currents ? If you try to pull a solid piece of some metals (good electrical conductors) quickly between the poles of a strong magnet, you will feel a force pushing

Computing the electric potential at a particular point, When one is computi...

When one is computing the electric potential at a particular point in space due to a continuous charge distribution what exactly is one calculating? Ans: The electric poten

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