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

State the faraday laws of electromagnetic induction, a.  State the Faraday'...

a.  State the Faraday's laws of electromagnetic induction. b.  A conducting circular loop is placed in an uniform magnetic field B=0.020 T with its plane perpendicular to the fi

Explain longitudinal waves, Longitudinal Waves: The traveling waves in ...

Longitudinal Waves: The traveling waves in which particles of the elastic medium vibrate about back and forth along the direction of propagation of waves are called longitudina

The force is in newton, The force is in Newton The buoyant (upward) for...

The force is in Newton The buoyant (upward) force exerted by water on a submerged object is given by the formula F= ?Vg, where ? is the density of water (1.0 x 10 3 kg/m 3 ),

How many electrons possesses by germanium, Germanium possesses (A) One...

Germanium possesses (A) One valence electrons. (B) Two valence electrons. (C) Three valence electrons. (D) Four valence electrons. Ans: Germanium possess

What are the basic requirements of a laser, What are the basic requirements...

What are the basic requirements of a Laser? Basic requirement of a Laser are as follows: 1. Active Medium: Active basic medium is needed to start the laser action. There

Brownian motion, Brownian motion (R. Brown; 1827) It is the continuous...

Brownian motion (R. Brown; 1827) It is the continuous random motion of solid microscopic particles while suspended in a fluid medium because of the consequence of ongoing bomb

Lambert''s laws, Lambert's laws (J.H. Lambert): Lambert's first law ...

Lambert's laws (J.H. Lambert): Lambert's first law The illuminance on a surface illuminated through light falling onto it perpendicularly from a point source is propor

Index of refraction to a medium, On transitory from a medium with one index...

On transitory from a medium with one index of refraction to a medium with a different index of refraction light is typically both reflected and refracted. Under some conditions how

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