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

Equations of linear motion for uniform acceleration, Given a particle movin...

Given a particle moving along a straight line with fixed acceleration a. Let u be the initial velocity of the particle and v be the velocity at time t. So by definition,

Define persistence of hearing, The impression of sound heard by our ears pe...

The impression of sound heard by our ears persist in our mind for 1/10th of a second. If another sound is heard before 1/10 second is over, the impression of the two sound mixes up

Determine the elapsed time in kinematics, Q. Determine the elapsed time in ...

Q. Determine the elapsed time in kinematics? Let S = 1 + c 2 + c 4 + ........  Then, S = 1 + c 2 (1 + c 2 + c 4 +.......... ) S = 1 + c 2 S    so, S - c 2 S = 1

Is soccer balls go faster in the air on a cold or hot day, Q. Illustrate th...

Q. Illustrate that soccer balls go faster in the air on a cold or hot day? Answer:- On a hot day the air molecules have additional kinetic energy they move around more fre

Measuring with a micrometer caliper, Measuring with a Micrometer Caliper ...

Measuring with a Micrometer Caliper A simple animation of using a micrometer to measure the width of a pencil.

Evaluate the potential energy of the ball, A ball with a mass of 25 grams i...

A ball with a mass of 25 grams is dropped from ledge 908 meters above the ground. What is its kinetic energy the instant before it hits the ground? What is the potential energy of

What is the magnitude of the centripetal acceleration, There is a clever ki...

There is a clever kitchen gadget for drying lettuce leaves after you wash them. It consists of a cylindrical container mounted so that it can be rotated about its axis by turning a

Light is able to travel through vacuum, Light is able to travel through vac...

Light is able to travel through vacuum Ans: In classical physics electromagnetic radiation (light) is the only kind of wave that doesn't need a medium. For sound rays in a

How far does the boat coast, A power boat of mass 500 kg is cruising at a c...

A power boat of mass 500 kg is cruising at a constant speed of 8.9 m/s. The propeller provides a drive force of 765 N. The driver of the boat shuts off the engine, and the boat coa

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