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

Diamond dosimetry, what is the working principle of diamond dosimeter and w...

what is the working principle of diamond dosimeter and whast are its advantages and disadvantages over other dosimeters?

Heart, how many pumps does the heart pumps

how many pumps does the heart pumps

Acceleration on the earth, Do objects of different weights fall with same a...

Do objects of different weights fall with same acceleration on the earth? Yes , objects fall with the similar acceleration regardless of their weights at the surface of earth,

Find the minimum wavelength of a bremsstrahlung photon, a. Consider an x-ra...

a. Consider an x-ray machine with a step-up transformer consisting of a primary coil of 100 turns and a secondary one with 50000 turns. If the voltage applied across the primary co

Vitreous enamel capacitors, These capacitors are made using vitreous enamel...

These capacitors are made using vitreous enamel on mixture of silica, alkali oxides and fluorides as dielectrics. These capacitors are formed by spraying vitreous lacquer on metal

Anthropic principle, weak anthropic principle The conditions compulso...

weak anthropic principle The conditions compulsory for the growth of intelligent life will be met only in certain regions which are restricted in space and time. i.e., the re

Coulomb, Coulomb; C (after C. de Coulomb, 1736-1806) The derived SI un...

Coulomb; C (after C. de Coulomb, 1736-1806) The derived SI unit of electric charge, described as the amount of charge transferred through a current of 1 A within a period of 1

Define amperes circuital law, Q. Define: ampere's circuital law. The l...

Q. Define: ampere's circuital law. The line integral → → for a closed curve is equivalent to μo timesthe net current Io B . d l   By the area bounded by the curve.

Optics, explain the working of michelson interferometer

explain the working of michelson interferometer

Explain electrolysis, The phenomenon of decomposition of electrolyte soluti...

The phenomenon of decomposition of electrolyte solution into ions on passing the current by it is called electrolysis. Practical functions of electrolysis are Electrotyping, ext

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