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

Magnitude of a point charge, a) Two charges of the value 15X10 -9 coulomb ...

a) Two charges of the value 15X10 -9 coulomb and 30X10 -9 coulomb are locate at a distance 6 cm. Determine the intensity of electric field at point which is at a distance 2 cm fro

Project, i want to make a project of electromagnetic induction

i want to make a project of electromagnetic induction

Evolution of hydrogen , A strip of aluminium of mass 40.7g is dropped into ...

A strip of aluminium of mass 40.7g is dropped into a beaker of dilute hydrochloric acid. Calculate the work done (in J) on the surrounding atmosphere (1atm pressure, 26.1 o C ) by

Typical signal source and amplifier circuit, 1. Discuss the internal noise ...

1. Discuss the internal noise sources that are present in a typical signal source and amplifier circuit, and describe their effects.  2.  The company currently has a low noise a

Maxwell-ampere-s-law-2-quation, Maxwell''s equations are a set of partial d...

Maxwell''s equations are a set of partial differential equations that, together with the Lorentz force law, form the foundation of classical electrodynamics, electric circuits and

What is utilisation count, What is Utilisation Count? Utilisation Count...

What is Utilisation Count? Utilisation Count shows status of every processor in a particular mode it implies that overhead mode, idle mode and busy mode with respect to progres

The effects of short circuits, The effects of short circuits: A short c...

The effects of short circuits: A short circuit is a path for current where a path should not exist, the path is generally considered to have a low resistance. If a short circui

At what rate would you lose energy, you were to walk briefly in space witho...

you were to walk briefly in space without a spacesuit while far from the Sun (as an astronaut does in the movie  2001 ), you would feel the cold of space --while you radiated energ

Explain what is light, Q. Explain what is light? Light is certainly ele...

Q. Explain what is light? Light is certainly electromagnetic radiation but the expression electromagnetic radiation is by no means an explanation of what light is. Light is a w

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