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

What are the consequences of dispersion, What are the consequences of dispe...

What are the consequences of dispersion? The main familiar result of dispersion is the splitting up of the composite white light within its constituent colours as into a rainbo

Capacitance, Capacitance: If we increase the voltage between the plates...

Capacitance: If we increase the voltage between the plates, the charge increases, but the ratio of charge to voltage remains the same.  This ratio gives the capacitance (C)  of

Generate a gaussian random signal vector, Generate and plot a sampled sine ...

Generate and plot a sampled sine wave with fs=8kHz, of 4 seconds duration, with frequency ?0 = ?/10 and amplitude A = 1.2. The waveform equation is x(n) = A sin n?

Carbon composition resistor, MANUFACTURING: T hese resistors do not require...

MANUFACTURING: T hese resistors do not require substrate. Resistive material is a mixture of finally ground graphite, filter and resin blander. Filter is usually silica. The mix is

Magnetic field and electric current., the magnetic field at a dictance of 2...

the magnetic field at a dictance of 2cm from the axis of a straight conductor carrying current is 12mT.Find the currentin the conductor?

What is the magnitude of the horizontal force, A man pushes a couch a dista...

A man pushes a couch a distance of 0.75 m. If 113 J of work is done. what is the magnitude of the horizontal force applied?

What are the alternatives to prevent tuberculosis, Alternatives to prevent ...

Alternatives to prevent tuberculosis - Another possible regimen for treatment of latent TB is daily rifampin alone for 4 months, which may be useful in persons intolerant to is

Advantages of a.c. transmission of power, Advantages of A.C. transmission o...

Advantages of A.C. transmission of power 1. The power can be produced at high voltages. 2. The maintenance of a.c. sub-stations is simple and cheaper. 3. The a.c. voltage

Explain periodic motion, When a body or a moving particle repeats its motio...

When a body or a moving particle repeats its motion along an exact path after regular parts of time, its rotation is said to be Periodic Motion and interval of time is known as per

Acceleration, suppose you are running and want to stop at once. surely you ...

suppose you are running and want to stop at once. surely you will have to produce negative acceleration in your speed. can you tell from where does the necessary force come ?

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