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

Impact of a dielectric on the behaviour of a capacitor, C onsid er that two...

C onsid er that two large paralle l plates forming a capacitor are separated by a distance d with vacuumed as the dielectric medium between the plates. The plates are connected to

De - broglie waves theory, Q. Explain the wave nature of matter.   De -...

Q. Explain the wave nature of matter.   De - Broglie Waves Theory According to De - Broglie hypothesis, particles like electron, proton, neutron etc. show wavelike properti

Calculate uniform magnetic field, The greatest induced EMF will happen in a...

The greatest induced EMF will happen in a straight wire moving at constant speed by a uniform magnetic field. when the angle among the direction of the wire's motion and the di

Curie weiss law for ferromagnetism, The first question one might ask about ...

The first question one might ask about ferromagnetic material is the source of the large magnetism. The saturation magnetization is so large virtually all the magnetic dipoles in t

Reducing friction with pencils, Reducing friction with pencils Place ro...

Reducing friction with pencils Place round pencils under a heavy box. Join a string to the box and find the force required to move it across a table. Search the force needed to

#titleprojection of body from inclined plane.., Awhat is angle of projectio...

Awhat is angle of projection of body thrown from inclined plane of 37degree so that body hits inclined plane normalysk question #Minimum 100 words accepted#

Who first theoretically predicted the existence of positron, Who first theo...

Who first theoretically predicted the existence of the positron, a positively charged electron?  He received the Nobel Prize in Physics in 1933. Ans: (Paul Adrien M

What are the mean energy transferred - photon interactions, Photon Interact...

Photon Interactions a. Consider a Si detector of 1 mm thickness. 10 6 photons each with energy of 100 keV are incident on the detector. Find the number of coherent, Compton, an

Explain time of flight, TIME OF FLIGHT: "It is the total time for which...

TIME OF FLIGHT: "It is the total time for which the projectile remains in air". As, the body goes up and comes back to similar level, so it does not cover vertical distance,

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