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

Describe snells law, Out of ordinary and extra-ordinary waves, which wave o...

Out of ordinary and extra-ordinary waves, which wave obeys Snell's law?

Units and dimensions, what is the dimension and unit of bulk modulus,stress...

what is the dimension and unit of bulk modulus,stress,strain and moment of interia

Explain units of coulomb and candle, Coulomb: Coulomb is the fundamental u...

Coulomb: Coulomb is the fundamental unit of charge. It is explained as the charge required to obtain 9?109 newton of force among two equal charges separated at a distance of one m

Quantum particle confined to one dimensional box, A quantum particle confin...

A quantum particle confined to one dimensional box of width 'a' is in its first exited state. What is the probability of finding the particle over an interval of (a/2) marked symme

Degenerate and non-degenerate semiconductor, THE SEMICONDUCTOR in which num...

THE SEMICONDUCTOR in which number of electrons or holes is smaller than N c  and N v  density of state in CB or VB are called non-degenerate semiconductor. The general exponential

Define beats, When two dissimilar sound rays of slightly different frequenc...

When two dissimilar sound rays of slightly different frequencies, traveling in a phase along the same direction, superimpose on one other, the intensity of the resultant sound at a

Describe reverberation time and absorption coefficient, Describe "Reverbera...

Describe "Reverberation time" and "Absorption coefficient". Illustrate Sabine's formula for reverberation time in a closed auditorium.

Optical coherence tomography, Assume we place a screen with two parallel sl...

Assume we place a screen with two parallel slits right in front of a lens (with focal distance f ), and illuminate with light (at wavelength λ) from far away. (a) What will be the

Force constants, what is the force constants of Gd2MoO6?

what is the force constants of Gd2MoO6?

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