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

Pesudo force, Ask questidefination and explanation of pesudo force on #Mini...

Ask questidefination and explanation of pesudo force on #Minimum 100 words accepted#

Calculate the volumetric substrate utilization rate, Batch fermentation ...

Batch fermentation For aerobic cultivation of yeast the cell mass concentration, X t , and the concentration of the limiting substrate component (glucose), S t , has been deter

Explain the trajectory of the particle, Question: A positively-charged ...

Question: A positively-charged particle is travelling southward in a downward-directed uniform magnetic field. The magnetic force is the merely force if any acting on the parti

How does one know which way to draw the current, Ques: In putting Kirch...

Ques: In putting Kirchoff's voltage law one draws a schematic diagram of the circuit and then indicates the current in each leg (a.k.a. branch) of the circuit. For every leg of

Wha is commutator, Commutator: The commutator is a form of rotating swi...

Commutator: The commutator is a form of rotating switch placed among the armature and external circuit and so arranged that it will reverse the link with the external circuit a

Compare the resistances, Two resistances have lengths in the ratio 1:4 and ...

Two resistances have lengths in the ratio 1:4 and radius 1:2,specific resistances in ratio 3:1. compare their resistances. Solution) Given lengths l1=1                          l

Cathode rays have, Cathode rays have: (1)Mass only (2)Charge only ...

Cathode rays have: (1)Mass only (2)Charge only (3)No mass and charge (4)Mass and charge both Ans:(4)Mass and charge both

What do you mean by photo electric effect, What do you mean by photo electr...

What do you mean by photo electric effect? Show the laws of photoelectric effect. Illustrate these laws using Einstein's equation of photo electric effect?

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