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

Electronics, define capacitor filter briefly?

define capacitor filter briefly?

Kinematics, the maximum height attained by a projectile and its horizontal...

the maximum height attained by a projectile and its horizontal range are equal to each other if the projectile projected at an angle [theta] given by ?

Absolute and relative permeability of a medium, Distinguish between absolut...

Distinguish between absolute permeability and relative permeability of a medium Absolute Permeability: 1. Absolute permeability is the ability of the medium to allow th

Explain newton’s law of cooling , It is described to this law, if the tempe...

It is described to this law, if the temperature T of the object is not very dissimilar from that of the environment T0, then rate of cooling -dT/dt is proportional to the temperatu

Atom, what is an atom

what is an atom

Can a solid and liquid together be possible, Can a solid and liquid togethe...

Can a solid and liquid together be possible? Actually, substances can exist in all three states of matter concurrently if the conditions are right. The triple point of a substa

Total polarization, In the presence of electronic, ionic and dipolar polari...

In the presence of electronic, ionic and dipolar polarization mechanisms, t he average induced  dipole moment per molecule will be the sum of all the contributions in terms of the

Determine the bending moment, Determine the Shear Force in kN rounded to 1 ...

Determine the Shear Force in kN rounded to 1 DP and Bending Moment in kN.m rounded to 1 DP at point C in the beam when the UDL on the beam is P52 kN/m (as for the previous question

Metallised paper capacitors, One side of impregnated paper capacitors is sp...

One side of impregnated paper capacitors is sprayed with metal.  When such paper is rolled, its gives higher capacitance for a given value. This capacitor has a self healing proper

How to do fun with a pendulum, Fun with a pendulum Suspend a hard ball ...

Fun with a pendulum Suspend a hard ball about 8 cm in diameter on a cord over a table. The cord should be at least 1.5 m in length and should be just high sufficient off the ta

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