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

Electric lines of force, Definition: The electric field in a region is show...

Definition: The electric field in a region is shown by continues lines (also known as lines of force). Field line is an imaginary line along which a positive test charge will move

Motion, the average speed of an object over a given time duration is 6 m/s....

the average speed of an object over a given time duration is 6 m/s. If it travels first half of the duration with a constant speed 4 m/s, its speed during the next half duration is

Use of monetary and fiscal policy, The government uses monetary and fiscal ...

The government uses monetary and fiscal policy to mitigate the effects of economic fluctuations

Experiment of the path of a projectile, Path of a projectile The appara...

Path of a projectile The apparatus below can be used to indicate the independence of the horizontal and vertical velocities of a projectile. The projectile is a metal ball, and

What are thomson effects and peltier, What is seebeck effect. Illustrate ho...

What is seebeck effect. Illustrate how thermo emf varies with temperature in a thermocouple, describe neutral and invertion temperature. What are Thomson effects and Peltier? D

What frequency does a stationary listener hear the sound, An airplane trave...

An airplane traveling at  v  = 187 m/s emits a sound of frequency 5.80 kHz. At what frequency does a stationary listener hear the sound during each of the following times? (Use344

Microwave Radiative Transfer in the Atmosphere, I''m transmitting microwave...

I''m transmitting microwave radiation from antenna to satellite..so when radiation(photons) is transmitted,how they interact with the molecules in the atmosphere layer by layer..I

Show the linked representation of the graph, Q. Show the linked representat...

Q. Show the linked representation of the graph.                                                            Ans: The linked representation of given graph is:

Explain centre of mass, Each physical system has related with it a certain ...

Each physical system has related with it a certain point whose motion characterizes the motion of the whole system. When the system goes under some external forces than this point

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