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

Differential equation for a simple harmonic oscillator, Write down the diff...

Write down the differential equation for a simple harmonic oscillator subjected to a damping force proportional to the velocity (v) of the oscillator and the periodic force of angu

Determine a static capacitor, A 250V, 50Hz single-phase supply feeds the fo...

A 250V, 50Hz single-phase supply feeds the following loads (i) incandescent lamps taking a current of 10A at unity power factor, (ii) fluorescent lamps taking 8A at a power

Bcs throry, bcs theory of superconductivity.

bcs theory of superconductivity.

The effects of the angle of the sun''s rays, Demonstrating the effects of t...

Demonstrating the effects of the angle of the sun's rays on the quantity of heat and light received by the earth Bend a piece of cardboard and make a square tube 4 cm2 in cros

Cro, explain the function of various type of screen in cro ?

explain the function of various type of screen in cro ?

Determine the humidity of air by different thermometers, The humidity of ai...

The humidity of air can be determined by use of two different thermometers; a 'dry bulb' thermometer and a 'wet bulb' thermometer.  With reference to a suitable text book, explain

SAFA, Physics assignment electron microscopy component, solve problem. can ...

Physics assignment electron microscopy component, solve problem. can u solve these two problems with detailing and referencing if it needed

Determine about the stacking fault, Determine about the Stacking fault     ...

Determine about the Stacking fault       Stacking faults happen in a number of crystal structures, but the common example is in close-packed structures.  Face-cantered cubic (f

Basic elactronics, recombination of electrons and holes impurity semiconduc...

recombination of electrons and holes impurity semiconductor

Experiment of a uniform motion, Uniform motion When a body falls by a f...

Uniform motion When a body falls by a fluid, the pull of gravity is soon balanced by the frictional forces set up, and it continues to move at a constant velocity. If this is t

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