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

Heat, the water flowing over the Niagara Falls drops a distance of 50 m. as...

the water flowing over the Niagara Falls drops a distance of 50 m. assuming that all the gravitational energy is converted to thermal energy, by what temperature does the water ris

What''s the way of the force if exerted on charged particle, Q. What's the ...

Q. What's the way of the force if exerted on charged particle? Described below is a positively charged particle in a rightward-directed electric field. The particle has a veloc

Hubbles law, Hubble's law (E.P. Hubble; 1925): A relationship discover...

Hubble's law (E.P. Hubble; 1925): A relationship discovered among distance & radial velocity. Further away a galaxy is away from is, the quicker it is receding away from us. T

Kilometers, Your car gets 34.7 mi/gal on a trip. How many kilometers/liter ...

Your car gets 34.7 mi/gal on a trip. How many kilometers/liter did it get?

Derive the relation at spherical surface concave, Derive the mathematical r...

Derive the mathematical relation connecting n,u,v and R for refraction at a spherical surface concave towards a point object in a denser medium.

Find the density on a hot day, The density of gasoline at 0 degrees C is 0...

The density of gasoline at 0 degrees C is 0.68 x103 kg/m3 What is the density on a hot day when the temperature is41 degrees C? What is the percentage change (+/-)?

Determine the exaggeration produced by the two lens system, Q. (a) Determin...

Q. (a) Determine the'effective  focal length' of the grouping of the two lenses in Exercise 9.10 if they are placed 8.0 cm a part with their principal axes  coincident. Performed t

Optical instrument, difference b/w concave grating and rownald mounting

difference b/w concave grating and rownald mounting

Electronics, tell the fixed transistor bias and describe the design

tell the fixed transistor bias and describe the design

What do you mean by thin prism, What do you mean by thin prism? and What i...

What do you mean by thin prism? and What is the lateral shift given by a parallel sided glass slab for grazing incidence of light?

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