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

What is diffraction of light, What is diffraction of light? Illustrate a gr...

What is diffraction of light? Illustrate a graph showing the variation of intensity with angle in a single slit diffraction experiment. Write single feature which distinguishes the

What is the average power consumption, The electric utility invoice for a h...

The electric utility invoice for a household shows a usage of 1245 kWh during a certain 30-day period. What is the average power consumption during this period?

heat transfer, Heat may be transmitted from one body to the other by any o...

Heat may be transmitted from one body to the other by any of three possible ways: conduction, radiation and convection.  In the conduction, convection phenomena, a medium is essent

Draw a ray diagram to show the formation of image, Draw a ray diagram to sh...

Draw a ray diagram to show the formation of image of an object placed among the optical centre and focus of the convex lens. Write the characteristics of image formed. Using this d

Calculate the magnitude of the magnetic field , A 240-turn solenoid having ...

A 240-turn solenoid having a length of 21 cm and a diameter of 8.8 cm carries a current of 0.44A. Calculate the magnitude of the magnetic field inside the solenoid.

Determine the coefficient of thermal expansion, 1) The potential energy be...

1) The potential energy between two atoms can be represented as follows: where A and B are constants and r the interatomic separation distance in metres. Plot the potential ene

The medium is air, Determine the inductance of a solenoid of 2000 turns rou...

Determine the inductance of a solenoid of 2000 turns round uniformly over a length of 50 cm on a cylindrical paper tube 4 cm in diameter. The medium is air.

Energy, Energy: The term energy may be defined as the capacity for doin...

Energy: The term energy may be defined as the capacity for doing work.  There are two forms of energy: potential energy and kinetic energy. POTENTIAL ENERGY Potential e

Q, #question 1:successive disintegration in nucluer physics

#question 1:successive disintegration in nucluer physics

Who first american physicist win two nobel prizes, What is the name of the ...

What is the name of the first American physicist to win two Nobel prizes? Ans: (John) bardeen was the first American physicist who win two Nobel prizes.

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