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

Compute the reactance of capacitor, Q. A capacitor of capacitance 2 μF is i...

Q. A capacitor of capacitance 2 μF is in an ac circuit of 1000 Hz. Compute the reactance of it. Solution: Capacitive reactance XC        = 1 / ω C = 1 / 2π ν C =

Draw a single stage amplifier circuit using JFET, Draw  a  single  stage  a...

Draw  a  single  stage  amplifier  circuit  using  JFET  Circuit  of  a  Single  Stage  Common  Source  N-channel  JFET amplifier  using self-bias is shown in figure

Define the cylinders and heat bath, Define the Cylinders and Heat Bath? ...

Define the Cylinders and Heat Bath? Regard as a cylinder 1 m long with a thin, massless piston clamped in such a manner that it divides the cylinder into two equal parts. The

Explain the reason when chemical changes, Chemical changes during: Dis...

Chemical changes during: Discharging: The current will flow from positive to negative plate in the external circuit. As current now enters by negative plate, the negative

Splitting of signals is caused by, Splitting of signals is caused by: (...

Splitting of signals is caused by: (1) Proton (2) Neutron (3) Positron (4) Electron Ans: (1) Proton

What do you mean by an optical fiber, What do you mean by an optical fiber?...

What do you mean by an optical fiber? State its principle. Can we minimize chromatic and spherical aberrations simultaneously? If so, how?

Gases, Imagine a car tire that contains 5.1 moles of air when at a gauge pr...

Imagine a car tire that contains 5.1 moles of air when at a gauge pressure of 2.1×105N/m2 (the pressure above atmospheric pressure) and a temperature of 27 °C. The temperature incr

Heisenberg uncertainty principle, It is explained by Heisenberg's uncertain...

It is explained by Heisenberg's uncertainty principle, it is impossible to calculate simultaneously both the position and the momentum of the particle. Let x and p be the uncert

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