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

First law of black hole dynamics, Black-hole dynamic laws; laws of black-ho...

Black-hole dynamic laws; laws of black-hole dynamics first law of black hole dynamics For interactions among black holes & normal matter, the conservation laws of mass-

Define wave function, It is a mathematical explanation of the disturbance p...

It is a mathematical explanation of the disturbance prepared by a ray. For a string, the wave function is a distance for sound rays. It is a density or pressure fluctuation while f

Minimum real charge on any particle which can exist, The minimum real charg...

The minimum real charge on any particle which can exist is: (1)1.6x 10 -19 coulomb (2) 1.6x 10 -10 coulomb (3)4.8 x 10 -10 coulomb (4)Zero Ans: (1)1.6x 10 -19 c

Image of this object formed in concave mirror-wave optics, The focal length...

The focal length of a concave mirror is 2 meters. An object is positioned 8 meters in front of the mirror. Where is the image of this object formed? Ans: The image of given ob

Describe kirchoffs voltage law, Describe Kirchoff's Voltage Law? Ans. I...

Describe Kirchoff's Voltage Law? Ans. It describe, " the sum of the Voltage drops around a DC series circuit same to the applied voltage or source. E = E 1 + E 2 = E 3 .

Determine watts of power dissipated for potential difference, The constant ...

The constant potential difference across a 2 ohm resistor is 20 volts. How many watts of power are dissipated by this resistor? Ans: 200 watts of power are dissipated throug

Classes of magnetic materials: antiferromagnetism, Anti ferromagnetic mater...

Anti ferromagnetic materials such as chromium have a small but positive susceptibility. They cannot possess any magnetization is the absence of an applied field, in contrast to fer

Magnetic poles, Magnetic poles: The two regions near the ends of a magn...

Magnetic poles: The two regions near the ends of a magnet at which the attracting forces appear to be concentrated are called the magnetic poles. The pole (when freely suspende

Definition of semiconductors, Definition of semiconductors Photovoltaic...

Definition of semiconductors Photovoltaic (PV) cells are made of special materials known as semiconductors like as silicon, which is currently the most commonly used. Basically

Watt, Watt; W (after J. Watt, 1736-1819): The derived SI unit of power...

Watt; W (after J. Watt, 1736-1819): The derived SI unit of power, explained as a power of 1 J acting onto a period of 1 s; thus it has units of J/s.

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