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

Conductivity of extrinsic semiconductor with temperature, The conductivity ...

The conductivity of an extrinsic semiconductor (A) Decreases with temperature. (B) Increases with temperature. (C) Remains constant with temperature. (D) Decrea

Are certification important in the fiber optics industry, Are certification...

Are certification important in the fiber optics industry? It will depend upon the type of certificate, what is certified and through who is granted. Several certifications refe

Difference between the atomic theory and the kinetic theory, What is the di...

What is the difference between the Atomic Theory and the Kinetic Theory? Atomic theory is all about structure of an atom, i.e., its composition. Like an atom in general is made

Current during the resistor, Ques: A 12 volt battery is associated in...

Ques: A 12 volt battery is associated in series with an initially-uncharged 120 microfarad capacitor and a 25 ohm resistor. What is the current during the resistor at the ins

Magnetic monopole, Magnetic monopole A hypothetical particle that sink...

Magnetic monopole A hypothetical particle that sinks of the magnetic field & constitutes sources. Magnetic monopoles have never been determined, but would cause fairly minor m

Thin films, Surface crystallography and epitaxy. Fe thin films are grown o...

Surface crystallography and epitaxy. Fe thin films are grown on a single-crystal Al(100) substrate surface. The films grow with no dislocations (if they are thin enough) with sug

Plastic capacitors, Since polymeric materials can be formed in thin, highly...

Since polymeric materials can be formed in thin, highly uniform and non porous films with high dielectric strength, these materials are preferred dielectric materials for capacitor

Ionising argon, An atom of argon(18 protons, 19 neutrons) is ionised by the...

An atom of argon(18 protons, 19 neutrons) is ionised by the removal of two orbiting electrons. Q) How many protons and neutrons are there in this ion?

Explain torque, A 92-kg man uses a 3.05-m board to attempt to move a boulde...

A 92-kg man uses a 3.05-m board to attempt to move a boulder, as shown in the diagram below. He pulls the end of the board with a force equal to his weight and is able to move it t

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