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

Describe positive rays, Positive rays are sometimes called as the canal wav...

Positive rays are sometimes called as the canal waves. These were found by Goldstein. If the cathode of a discharged tube has holes in it and the pressure of the gas is around 10-3

Schottky barrier diodes, The Schottky diodes are a semiconductor diode with...

The Schottky diodes are a semiconductor diode with a low forward voltage drop and a very fast switching action. The voltage drop at forward biases of around 1ma is in the range 0.1

Find the x-component of the electric field, Presume that you are given an e...

Presume that you are given an expression for the electric potential V(x,y) as a function of x and y valid for points in the first quadrant of a Cartesian coordinate system and aske

Explain the strength of the electromagnet, Consider the sketch of the elect...

Consider the sketch of the electromagnet in the figure below. Which components could you change to increase or reduces the strength of the electromagnet? Describe your answer.

Diesel and flat car- inelastic collision, Diesel and Flat Car The anima...

Diesel and Flat Car The animation below portrays the inelastic collision among a extremely massive diesel and a less massive flatcar. Previous to the collision, the diesel is i

WORK AND ENERGY, A boy throws a ball of mass 20 kg vertically upwards.It ra...

A boy throws a ball of mass 20 kg vertically upwards.It raises to a maximum height of 100 m.At what height will the kinetic energy be reduced to 70%?

What is a fiber optic sensor, What is a fiber optic sensor? Fiber optic...

What is a fiber optic sensor? Fiber optic sensor: A fiber optic sensor is a sensor which uses optical fiber either like the sensing tool ("intrinsic sensors"), or implies as

Clamper, assignment of clamper

assignment of clamper

Concave grating, give the theory of concave grating and Rowland mounting

give the theory of concave grating and Rowland mounting

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