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

What is the magnifying power of the microscope, Q. A compound microscope co...

Q. A compound microscope consists of an objective lens of focal length 2.0cm and an eye piece of focal length 6.25cm separated by a distance of 15cm.How far from the objective sho

Magnetism, what is the magnetic field at a distance l from the centre of th...

what is the magnetic field at a distance l from the centre of the circle of radius r which carries a current i

If two soap bubbles of different radii are connected by tube, If two soap b...

If two soap bubbles of different radii are connected by a tube then, what happen? Ans) When these bubbles are joined through tube..the smaller bubble(with more pressure) gets its

Explain process of resonance, Resonance: When the frequency of driving...

Resonance: When the frequency of driving force becomes equivalent to the natural frequency of an oscillating system, the driving force gives maximum energy and the oscillating

Define about the set-up of helium-neon laser, Define about the set-up of He...

Define about the set-up of Helium-Neon Laser. The laser radiations along with higher coherence, higher directionality and higher monochromacity can be obtained from this. But,

Magnetism, Magnetism: Everyone has seen and handled a magnet in the f...

Magnetism: Everyone has seen and handled a magnet in the form of a straight or horseshoe-shaped bar of steel or steel-alloy. The magnet was originally a piece of steel befor

What is the angle of reflection, Question As-per to the law of reflect...

Question As-per to the law of reflection the angle of reflection is equal to the angle of incidence. An angle is at all times an angular separation between two planes a direct

Boltzmann classical statistics, It describes the behaviour of a collection ...

It describes the behaviour of a collection of a particle N(E) with gives energy through N(E)α exp(-E/KT) where K is Boltzmann constant. It can be explained as a collection of

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