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

Classes of magnetic materials: antiferromagnetism, Anti ferromagnetic mater...

Anti ferromagnetic materials such as chromium have a small but positive susceptibility. They cannot possess any magnetization is the absence of an applied field, in contrast to fer

Capacitor, how increase and decrease in the area of capacitor affects and h...

how increase and decrease in the area of capacitor affects and how the space maintained between two plate affect the capacitor with the help of diagram.

Experiment of serviceable spring balance, A serviceable spring balance ...

A serviceable spring balance The quality of rubber deteriorates rather rapidly in unfavourable climatic conditions; a coiled steel spring is preferable. The pattern defined ha

Fringes, What is the definition of fringes

What is the definition of fringes

1 dimensional motion, 2 cars, 1 and 2 starting from rest are moving with sp...

2 cars, 1 and 2 starting from rest are moving with speeds v1 and v2 m/s(v1>v2). car 2 is ahead of car1 by ''s'' metres when the driver of car 1 sees car 2. what minimum retardation

Expermient of steelyards, Steelyards Either Roman or Danish steelyards ...

Steelyards Either Roman or Danish steelyards can be improvised using short lengths of lead or iron water pipe as counter-weights and loops of wire s pivots. The rod can be o

Explain the thermal equilibrium, Explain the Thermal Equilibrium Thermal ...

Explain the Thermal Equilibrium Thermal Equilibrium occurs when one or more substances reach a common temperature by exchanging heat. When two substances come into thermal contac

Experiments on inertia - a bottle and marble, A bottle and marble Pour ...

A bottle and marble Pour some sand into a wide mouthed bottle. Place a piece of cardboard about 5 cm square over the mouth of the bottle. Set the marble on the cardboard and th

Explain current carriers, The charged particles whose flow in a exact direc...

The charged particles whose flow in a exact direction constitutes the electric current are known as current carriers. In separate positions current carriers are dissimilar. (i)

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