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

Fringes in youngs double slit experiment, How does the distance between fri...

How does the distance between fringes in Young's double slit experiment change. a) If the colour of the light is changed from red to blue? b) If the slit separation is incre

Types of superconductors, Type 1 and type 2 superconductors: For one gro...

Type 1 and type 2 superconductors: For one group of SUPERCONDUCTOR in which below H c is in the Meissner state, where it excludes all the magnetic flux from the interior of the

Define thermal conductivity, In solids, heat is move from conduction. We wi...

In solids, heat is move from conduction. We will study conduction of heat energy by a solid bar in the following section. Given a solid bar of thickness and area of cross-sectio

Simple harmonic motion, show that the oscillation of a liquid in a u-tube i...

show that the oscillation of a liquid in a u-tube is in simple harmonic motion

Earth rotations, Is the earth the perpetual motion machine

Is the earth the perpetual motion machine

Frame of reference, At what velocity a clock should move so that it seems s...

At what velocity a clock should move so that it seems slow by one minute in a day.

What is diffraction of light, What is diffraction of light? Illustrate a gr...

What is diffraction of light? Illustrate a graph showing the variation of intensity with angle in a single slit diffraction experiment. Write single feature which distinguishes the

Illustrate the polarity of barrier potential, Illustrate the polarity of Ba...

Illustrate the polarity of Barrier potential. The  free  electrons  which  cross  over  the  junction  recombine  with  the holes of p-type and uncover some of the negative ac

Thermal detectors method of detection of ultrasonic waves, Explain the ther...

Explain the thermal detectors method of detection of ultrasonic waves. Thermal detectors method: It is the most generally used method of detection of ultrasonic waves. In th

Earths rotation about its axis, The earth's rotation about its axis changes...

The earth's rotation about its axis changes measurably over time; You don't have to worry about the details; all you need to know is that our days are growing longer by about 2.3 m

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