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

Projectile motion, write all equationes of projectile motion used in calcul...

write all equationes of projectile motion used in calculation of vertical and horizontal motion

Illustrate the chemical vapour deposition method in brief, Illustrate the c...

Illustrate the chemical vapour deposition method in brief. Chemical vapour deposition method (CVD): A number of vapour phase deposition process have been developed for produ

A parallel plate capacitor each with plate area a, A parallel plate capacit...

A parallel plate capacitor, each with plate area A and separation d, is charged to a potential dissimilarity V. The battery used to charge it is then disconnected. A dielectric sla

What do you understand by absorption coefficient, What do you understand by...

What do you understand by "Absorption coefficient"? which is a better absorber of sound, glass or fibre glass?

Give basic postulate of special theory of relativity, Q. Give basic postula...

Q. Give basic postulate of special theory of relativity? A plane-convex lenses L of large radius of curvature with its convexities is placed on a plane glass plate P. When ligh

Refractive index, Refractive index: The most important optical measurem...

Refractive index: The most important optical measurement for any transparent material is its refractive index (n). The refractive index is the ratio of the speed of light (c)

Who makes fiber optics, Who makes fiber optics? Glass manufacturers mos...

Who makes fiber optics? Glass manufacturers mostly make Glass fibers. Mainly chemical companies fabricate PMMA fibers. Companies, both private and public, manufacture other kin

Heat engine in a typical fossil fuel power plant, Draw a picture of the hea...

Draw a picture of the heat engine in a typical fossil fuel power plant and explain how it works. 1.      ___________ is a measure of the electrical potential energy per free ele

Friction a necessary evil, Friction has several disadvantages but life is i...

Friction has several disadvantages but life is impossible without friction because friction has many benefits also.

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