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

Define thermometry, The temperature of a body is measured indirectly by mak...

The temperature of a body is measured indirectly by making use of the fact that certain physical property of a substance changes linearly with the temperature If the value of th

Effect on elasticity by different causes, (i) Effect of temperature: ...

(i) Effect of temperature: (a) In general elasticity reduces as the temperature increases. (b) Invar is an exception. There is no effect of temperature on elasticity of in

Stationary-orbits, According to uncertainity stationary orbits are accepted...

According to uncertainity stationary orbits are accepted or not?please give reason Ans) According to uncertainity stationary orbits are not accepted because according to station

What is elasticity, The characteristic of a body by virtue of which the bod...

The characteristic of a body by virtue of which the body takes its real configuration when external deforming forces are removed is called as elasticity.

Fluid Mechanics, True or False. The specific gravity of a fluid that sinks ...

True or False. The specific gravity of a fluid that sinks in water is greater than 1.00.

Double-slit experiment, Double-slit experiment (T. Young; 1801): A pop...

Double-slit experiment (T. Young; 1801): A popular experiment which illustrates the wave nature of light (and indeed of other particles). Light is passed out from a small sour

What is polymorphism, What is Polymorphism Polymorphism in materials sc...

What is Polymorphism Polymorphism in materials science is the skill of a solid material to exist in more than one form or crystal structure. Polymorphism can potentially be fou

Newton''s third law of motion, NEWTON'S THIRD LAW OF MOTION: This law c...

NEWTON'S THIRD LAW OF MOTION: This law can be described as "Actions and reactions are equal and opposite".                                  OR To every action there is a

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