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

Electric field intensity, A negative point charge 10 -8 coulomb is located...

A negative point charge 10 -8 coulomb is located in air at the origin of a rectangular coordinate system. What is the electric field intensity at a point on the positive x directi

Moment of inertia, define moment of inertia and it''s physical significance...

define moment of inertia and it''s physical significance

Digital electronics: binary system, (i) A number system which has only two ...

(i) A number system which has only two characters i.e. 0 (Low value) and 1 (High value) is known as binary system (ii) The electrical circuit which operates only in these two di

Rutherford''s atomic model, RUTHERFORD'S ATOMIC MODEL:- Rutherford prop...

RUTHERFORD'S ATOMIC MODEL:- Rutherford proposed that all the positive charge and mass of the atom was concentrated in a small central region which is called the nucleus.This mo

Time base control 2, Time Base Control 2 Shows the effect of modifying ...

Time Base Control 2 Shows the effect of modifying the time base control on the show while there is an input voltage varying in time.

Magnetic field is zero, Two parallel wires P and Q situated at a separation...

Two parallel wires P and Q situated at a separation of 6 cm carry electric currents i 1 =5 A and i2 = 2 A in opposite directions as given in fig-. Determine the point on the line

Explain voltmeter, Voltmeter: An electromechanical instrument which is ...

Voltmeter: An electromechanical instrument which is used to calculate potential difference among two points is known as voltmeter. Voltmeter is a modified form of a galvanom

Classes of magnetic materials: nickel iron alloys, It contains 35%- 90% nic...

It contains 35%- 90% nickels. Higher is the nickel content higher is the permeability and lower is the magnetic saturation of the alloy. MN, CO, and Mo can also be added in trace q

Simple harmonic motion, composition of two SHM at right angle to each other...

composition of two SHM at right angle to each other and having time period in the ratio of 1: 2

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