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 gausss law in electrostatics, Explain Gauss's law in electrostatics...

Explain Gauss's law in electrostatics? 1C of charge is same to the charge of n number of electrons in magnitude. What is the value of n? What happens to the force between t

Circular polarisation, Circular Polarisation Circular polarisation pro...

Circular Polarisation Circular polarisation produced from a linearly polarised electromagnetic wave through a quarter-wave plate.

Why hard ferrites are used, Hard ferrites are used for making (A) Tran...

Hard ferrites are used for making (A) Transformer cores.                      (B) Electrical machinery. (C) High frequency equipment.         (D) Light weight permanent m

How far down is the surface of the water, A hiker tosses a rock into a cany...

A hiker tosses a rock into a canyon. He hears it strike water 4.78 s later. How far down is the surface of the water?

Describe the term amorphous solids, Describe the term amorphous solids. ...

Describe the term amorphous solids. Amorphous solids: Solids along with particles not arranged in an ordinary fashion. They have merely short range order or still the partic

Maximum recombination time, Ask question how to plan and design a lab to me...

Ask question how to plan and design a lab to measure the maximum recombination time of ions produced by a flame

Is this wavelength in vacuum, Is this wavelength in vacuum? Answer; as ...

Is this wavelength in vacuum? Answer; as per mass of CPH is constant, and Vc is for an alone CPH, so wavelength should be in vacuum, that there is not any gravity effect. But i

Introduce concept about the carbon dioxide laser, Introduce concept about t...

Introduce concept about the carbon dioxide laser. A test target is vaporized and bursts within flame onto irradiation through a high power continuous wave carbon dioxide laser

Acceleration, suppose you are running and want to stop at once. surely you ...

suppose you are running and want to stop at once. surely you will have to produce negative acceleration in your speed. can you tell from where does the necessary force come ?

Charging a two-sphere system by induction using a negative, Charging a Two-...

Charging a Two-Sphere System by Induction Using a Negative Objects The below given animation depicts the induction procedure. Two neutral conducting spheres rest on top of insu

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