Voltage dependent resistor, Physics

Assignment Help:

A VDR is a special type of resistor that changes its resistance with rise in voltage. It has a very high resistance at low voltage (below the trigger voltage) and very low resistance at high voltage (above the trigger voltage). It is also called varistor or voltage sensitive resistor. There are two types of varistor.

SILICON CARBIDE VARISTOR:-              

MANUFACTURING: These are made up of silicon carbide. It is milled and mixed with a suitable ceramic binder. Then it pressed and extruded to desired shape of disc, rod or washer. Then it is sintered under controlled temperature to produce hard material. Wire leads are then connected.

METAL-OXIDE VARISTOR (MOV):

MANUFACTURING:

 Zinc oxide and bismuth oxides are mixed with other powdered metal additives, pressed into discs and sintered at 12000C. It has an encapsulated polycrystalline ceramic body; with metal contacts and wire leads.

APPLICATIONS: A varistor acts as a switch. It is usually used for short circuit protection in power strips or lightning bolts "arrestors" on street power poles. It is also used as a "snobbier" in inductive circuits.

 


Related Discussions:- Voltage dependent resistor

Explain the merits of vacuum diode over semiconductor diode, Explain the Me...

Explain the Merits of Vacuum Diode over Semiconductor Diode (i)  Vacuum Diodes can withstand high reverse voltages (ii)  Vacuum Diodes can operate at fairly high temperature

What must be the acceleration of the elevator, Alex is on the wrestling tea...

Alex is on the wrestling team and has a mass of 85.3 kg. Being a whiz at physics, he realizes that he is over the 830.0-N cut off for his weight class. If he can convince the train

Fermi dirac statistics, It determines the probability of an electron occupy...

It determines the probability of an electron occupying a state at an energy level E. This takes into account that a collection of electron must obey the Pauli Exclusion Principle.

Projectile motion, formula for height in a horizontal projection on an incl...

formula for height in a horizontal projection on an inclined plane?

Velocity, initial acceleration rocket is 0.01t in upward dirction initioal ...

initial acceleration rocket is 0.01t in upward dirction initioal velocity is 50ms-1 , what is the function for the velocity of the rocket?

binding power of a hydrogen molecules, Binding energy of a system is descr...

Binding energy of a system is described as the energy released when its constituents are brought from infinity to form the system. It can also be explained as the energy required s

When are intermolecular forces the strongest, When are intermolecular force...

When are intermolecular forces the strongest? Intermolecular forces (dipole-dipole, dispersion and hydrogen bonds). These forces are weaker than chemical (covalent) bonds. Thus

Relative permitivity, It is a measure of the extent up to which a materia...

It is a measure of the extent up to which a material concentrates electrostatic lines of flux. It is the amount of the stored electrical energy when a potential is applied, relat

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