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 intrinsic semiconductor, A pure semiconductor is known as intrinsic...

A pure semiconductor is known as intrinsic semiconductor. It has thermally formed current carriers (i)  They have four electrons in the outer part of orbit of atom and atoms are

WORK AND ENERGY, a boy throws a ball of mass 20 kg vertically upwards.it ra...

a boy throws a ball of mass 20 kg vertically upwards.it raises to a maximum height of 100 m.at what height will the kinetic energy be reduced to 70%

Homework, An ostrich can run at speeds of up to 72km/h. Suppose an ostrich ...

An ostrich can run at speeds of up to 72km/h. Suppose an ostrich runs 1.5km at the speed of 58 km/h and then runs another 1.5km at the speed of 29km/h. What is the ostrich average

Simple harmonic motion, Any motion which changes it after regular interval ...

Any motion which changes it after regular interval of time is known as periodic or harmonic motion. When the body of a pendulum moves to and fro through a short angle, the bob is k

Factor, Discuss the Factor affecting limiting current.

Discuss the Factor affecting limiting current.

Magnetic field and electric current., the magnetic field at a dictance of 2...

the magnetic field at a dictance of 2cm from the axis of a straight conductor carrying current is 12mT.Find the currentin the conductor?

Explain the meaning of nuclear fusion, Explain the meaning of Nuclear Fusio...

Explain the meaning of Nuclear Fusion Fusion happens when two light atoms like hydrogen or lithium combine. There is a net loss of mass which is converted to energy. The most f

Explain the nuclear notation?, Explain the Nuclear Notation? Chemical r...

Explain the Nuclear Notation? Chemical reactions deal with the number of electrons exchanged or shared.  Nuclear reactions, on the other hand, involve protons and neutrons and

Inelastic collision, INELASTIC COLLISION:  "The collision in which tota...

INELASTIC COLLISION:  "The collision in which total momentum is preserved but total K.E of system is not conserved is known as inelastic collision". It is to be noted that m

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