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

Ohmic, did the resistance of an ohmic conductor depends on the applied volt...

did the resistance of an ohmic conductor depends on the applied voltage

The charge and discharge characteristics of lead battery, The charge and di...

The charge and discharge characteristics of lead battery: During discharge the plates are converted into lead sulphate, the water content of the electrolyte increases, the inte

Explain destructive interference, Does destructive interference violate the...

Does destructive interference violate the principle of conservation of energy? Briefly explain.

Michelson morley experiment, Michelson Morley Experiment The Michelson...

Michelson Morley Experiment The Michelson-Morley experiment was performed within the year of 1887 through Albert Michelson and Edward Morley at what is presently Case Western

What are the stars, What are The Stars? The star is made of dust and ga...

What are The Stars? The star is made of dust and gas in space. Essentially it has many stages they are 1.black hole 2.nuetron star 3.supernova 4.red giant stage

Phenomenon of photoelectric effect?, A radiation of 500nm is incident on a ...

A radiation of 500nm is incident on a metal surface whose work function is 3ev.why do we not observe the phenomenon of photoelectric effect? Ans) Because the energy of radiation i

Classes of magnetic materials: alnico, Alnico is a family of alloys contain...

Alnico is a family of alloys containing metals Fe, Co and Ni plus small amount of Al and copper. These alloys are directionally solidified and subsequently given a heat treatment t

Moving the bar magnet rapidly away from the loop, Question: A wire loop...

Question: A wire loop smears in a horizontal plane. Alongside the loop is a vertical bar magnet south end up. The bar magnet is divide by the plane of the loop. A person is shi

Function of photodetectors in fibre optic communication, Define the functio...

Define the function of photodetectors in fibre optic communication system. Photo-detectors: At the receiver end, conversion of optical signal into analog signal is being don

Show the biasing of a light emitting diode, With the help of a diagram, sho...

With the help of a diagram, show the biasing of a light emitting diode (LED). Give its two benefits over conventional incandescent lamps.

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