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

consevation of angular momentum , It states that angular momentum of a sys...

It states that angular momentum of a system remains conserved if no net torque is acting on the system.

Describe solar cell, It is based on the photovoltaic effect. One of the sem...

It is based on the photovoltaic effect. One of the semiconductor regions is made so thin that the light incident on it reaches the p-n junction and gets absorbed. It changes solar

How high will it go, How High Will It Go? The motion of the sledder wit...

How High Will It Go? The motion of the sledder within the animation below is same to the motion of a roller coaster car on a roller coaster track. The similarity of the two mot

Experiment of cutting a glass dish from a used electric bulb, Cutting a gla...

Cutting a glass dish from a used electric bulb The hemispherical bottom of an electric light bulb gives a useful glass dish; a soldering iron can be used to cut it off. put the

Defect of vision, defect of vision project work 8&10 pages

defect of vision project work 8&10 pages

Explain momentum or linear momentum, MOMENTUM OR LINEAR MOMENTUM. It is...

MOMENTUM OR LINEAR MOMENTUM. It is described as "The product of mass and velocity of the body".                                 OR "The quantity of linear motion of a bod

Calculate the current needed to produce the flux, 1). A ring of outer diame...

1). A ring of outer diameter 80 cm is made from square of cross -section steel bar size(8 *8 cm) . If relative permeability 1200 for steel . calculate the current needed to produce

Artificial transmutation, The process of transformation of one element into...

The process of transformation of one element into another by bombarding it with high energy particles is called "Artificial transmutation". Artificial radio activity is the proc

How electric current passing by a conductor, What occurs to the power dissi...

What occurs to the power dissipation if the value of electric current passing by a conductor of constant resistance is doubled? Normal 0 false false false

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