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

Collision centre of mass a d linear momentum, Ask question #Minimum 100 wor...

Ask question #Minimum 100 wora cannon of mass 5m ( including a shell of mass m )is at rest on a smooth horizontal ground fires the shell with its barrel at an angle A with the hori

Write three special characteristics of the light source, Write three specia...

Write three special characteristics of the light source used in optical communication. Name any one optical detector. Define the meaning of the term 'sensitivity' and 'responsively

Propagation of an electromagnetic wave, Propagation of an Electromagnetic W...

Propagation of an Electromagnetic Wave Electromagnetic waves are waves that can travel by the vacuum of outer space. Mechanical waves, not like electromagnetic waves, need the

Sound problem, A Decibel meter reads 140 dB for a sound source at 20''c at...

A Decibel meter reads 140 dB for a sound source at 20''c at 60 % relative humidity. It also records sound pressure for 140 dB as 200 pascals what will it read( decibel meter) at 4

Capacitor has an amount of charge q on it, What do we denote when we say th...

What do we denote when we say that a capacitor has an amount of charge Q on it? Answer: If we obtain the expression the charge on the capacitor too accurately the value is

Is air travel time the similar whether or not, Q. Is air travel time the si...

Q. Is air travel time the similar whether or not the plane is flying with or against the rotation of the Earth? Answer:- All air travel gets the earth's rotation into acco

Explain the photoelectric electricity, Photoelectric electricity is produce...

Photoelectric electricity is produced directly from solar energy when which following are absorbed in a semiconductor to create an electric current? a)  Protons b)  Electron

Define surface contaminations (wisconsin-madison), Define Surface Contamina...

Define Surface Contaminations (Wisconsin-Madison)? A surface scientist wishes to remain an exposed surface "clean" (≤ 0.05 adsorbed monolayer) for an experiment lasting for tim

Why the bubble form in the spherical shape, The Bubble''s shape is spherica...

The Bubble''s shape is spherical so as to reduce the surface tension. With the given volume of liquid,Spherical surface only fits i minimizing the surface tension to a greater exte

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