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

What is electrostatic shielding, Q. What is electrostatic shielding? i...

Q. What is electrostatic shielding? i) It is the method of isolating a certain region of space from external field. ii) It is basis on the fact that electric field inside a

Calormetry, in water equivalent how the temperature or water and solid equa...

in water equivalent how the temperature or water and solid equal?

Calculation of speed of light, how to calculate speed of light?  The sp...

how to calculate speed of light?  The speed of light in vacuum, normally denoted by symbol c, is a universal physical constant which is very important in various areas of physi

Force between two magnetic poles, The force between two magnetic poles divi...

The force between two magnetic poles divided by a distance ‘d' in air is ‘F'. At what distance between them the force becomes doubled?

What are the safety terms to be inspected on battery, What are the safety t...

What are the safety terms to be inspected on battery? Ans: Safety terms to be checked on battery are full complements of battery box fixing bolts and its tightness, observat

Polymers, explanation on polymers tga curves

explanation on polymers tga curves

Explain the supply current, For the circuit shown in Figure , verify the va...

For the circuit shown in Figure , verify the value of V1. If the total circuit resistance is 36Ω. Determine the supply current and the value of resistors R 1 , R 2 and R 3

Bohr magneton, Bohr magneton (N. Bohr) It is the quantum of magnetic mo...

Bohr magneton (N. Bohr) It is the quantum of magnetic moment. Bohr radius (N. Bohr) It is the distance corresponding to the mean distance of an electron through the nuc

What are the basic components of lead acid cell, What are the basic compone...

What are the basic components of Lead Acid cell? Ans. Basic components of Lead Acid cells are: a) Positive Plates, which are tubular n shape, prepared by PBO 2 b) Negativ

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