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, Find the electric field between the plates of a capacitor given t...

Find the electric field between the plates of a capacitor given the following:? (1) C= 10pF (2) the capacitor is connected to a 25 V battery (3) there is a vacuum between the capa

Determine the superposition principle, Determine the Superposition Principl...

Determine the Superposition Principle The Superposition Principle for numerous electric potentials, unlike electric fields and forces, is summed algebraically.  Electric potent

Making an observation nest for ants, Making an observation nest for ants ...

Making an observation nest for ants An observation nest for the study of the life story of ants can simply be made as follows. Make a wooden U from three 30 cm lengths of w

Jet propulsion is made possible by action and reaction, Jet propulsion is m...

Jet propulsion is made possible by action and reaction Fit a small cardboard stabilizer to the neck of a balloon by means of adhesive tape. Inflate the balloon, and close the m

Draw a labelled diagram of van de graff generator, An a.c. voltage E = E 0 ...

An a.c. voltage E = E 0 sin cot is applied across an inductor L. Get an expression for current I. Draw a labelled diagram of Van de Graff generator. Verify its principle of wor

Determine atomic number and weight atomic number, Compared with an atom of ...

Compared with an atom of atomic weight 12 and atomic number 6, the atom of atomic weight 13 and atomic number 6: (1) Contains more neutrons         (2) Contains more electro

Resolution of forces, Resolution of Forces: This topic is important, bu...

Resolution of Forces: This topic is important, but is really the opposite to Addition of forces. Recalling that two forces can be added to give a single force known

Wave optics, can I get ready made project for wave optic?

can I get ready made project for wave optic?

Organic or polymer solar cells , Organic & polymer solar cells are made fro...

Organic & polymer solar cells are made from thin films (typically 100nm) of organic semiconductor such as polymer and small molecule compounds like poly phenylene vinylene, copper

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