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

Explain general theory of gravitation, Explain General Theory of Gravitatio...

Explain General Theory of Gravitation The idea of a gravitational field takes all the gravitational effects of a given mass like Earth and expresses them mathematically as a grav

Le chateliers principle, Le Chatelier's principle (H. Le Chatelier; 1888) ...

Le Chatelier's principle (H. Le Chatelier; 1888) If a system is in equilibrium, then any change imposed onto the system tends to shift the equilibrium to decrease the effect of

Explain phenomena of pendulum that suspended by railroad car, A pendulum wh...

A pendulum which is suspended from the ceiling of a railroad car is observed to hang at an angle of 10 degrees to the right of vertical.  Which of the following answers could expla

Special Relativity (massless), 1]What is the difference between a photon an...

1]What is the difference between a photon and a neutron? 2]Why are they massless?

What are the advantages of fibre optic communication, What are the advantag...

What are the advantages of fibre optic communication? Advantages of fibre optic communication are as follows: a. Enormous band width Coaxial cable transmission of 500 M

What is illumination, What is Illumination? A body that gives off light...

What is Illumination? A body that gives off light is called luminous, like all those glow-in-the-dark toys, and a body that gives off light when it is heated is called incandes

Illustrate what does gravitational force depend on, Q. Illustrate what does...

Q. Illustrate what does gravitational force depend on? Answer:- The Gravitational force depends on distance as well as mass. Therefore the formula for calculating gravitat

Explain electromagnetism, Electromagnetism: A temporary magnet formed b...

Electromagnetism: A temporary magnet formed by winding a coil of insulated copper wire around a piece of shift iron is known as electromagnet. When current is passed it behaves

Specific latent heat, explain specific latent heat of fusion with formula

explain specific latent heat of fusion with formula

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