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

Who female physicist who received the nobel prize in 1963, Name the female ...

Name the female physicist who received the Nobel Prize in 1963 for her discovery concerning the shell structure of the nucleus. Ans: (Maria Goeppert) Mayer was the first fe

Reflection law, Reflection law For a wavefront intersecting reflecting...

Reflection law For a wavefront intersecting reflecting surface, the angle of incidence is equivalent to the angle of reflection, in the similar plane described by the ray of i

Define the electromagnetic radiation, Diffraction is a phenomenon that is s...

Diffraction is a phenomenon that is severely associated with light. That is to utter that light and only light undergoes diffraction. (By light here we denote any form of electroma

Diffraction of water waves, Diffraction of water waves Let vibrator ...

Diffraction of water waves Let vibrator produce circular wavefronts travelling along (P). Let X, Y be two vertical glass plates immersed in the tank far away from the vib

Michelson interferometer, how Michelson interferometer can be used to measu...

how Michelson interferometer can be used to measure the wavelength of sodium light.

Valve & digital electronics: thermionic emission, (i) The procedure of ejec...

(i) The procedure of ejection of electrons from a metal surface by the application of heat is known as thermionic emission and emitted electrons are known as thermions and current

Free fall , wrench from the top of an 80 m high tower what is the velocity ...

wrench from the top of an 80 m high tower what is the velocity of the wrench when it strikes the ground?

Find the minimum angle at which a roadbed should be banked, Find the minimu...

Find the minimum angle at which a roadbed should be banked Determine the minimum angle at which a roadbed should be banked so that a car traveling at 20.0 m/s can safely negotia

How are the colloids classified on the basis of the nature, How are the col...

How are the colloids classified on the basis of the nature of interaction among dispersed phase and dispersion medium? Describe a significant characteristic of each class. Which of

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