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

Fiber optics manufacture and fiber optics system manufacture, What is the d...

What is the difference among a fiber optics manufacture and a fiber optics system manufacture? It is a question that would sound silly in other industries although not in this

Kirchhhoff''s second law, I have a circuit and using Kirchhoff''s second la...

I have a circuit and using Kirchhoff''s second law I need to find the current across one of the battery. How should I do that?

Young sun paradox, faint, young sun paradox Theories of stellar evolut...

faint, young sun paradox Theories of stellar evolution denote that as stars mature over the main sequence, they steadily grow hotter & brighter; calculations recommend that at

Draw the symbolic representation of a p-n-p and n-p-n, Draw the symbolic r...

Draw the symbolic representation of a (i) p-n-p, (ii) n-p-n transistor. Why is the base region of transistor thin and lightly doped? With proper circuit diagram, show the biasin

Newtons laws of motion, Newton's laws of motion (Sir I. Newton) Newto...

Newton's laws of motion (Sir I. Newton) Newton's first law of motion A body remain continues in its state of constant velocity (that may be zero) unless it is acted on

Average speed, A boy goes to market with a average speed of 29 km/h.He retu...

A boy goes to market with a average speed of 29 km/h.He returns back half the way he went with a average speed of 40 km/h.Find average speed for whole journey.

Explain about the coriolis effect, The Coriolis effect is a deflection of m...

The Coriolis effect is a deflection of moving objects when they are reflects in a rotating reference frame. In a reference frame with clockwise rotation, the deflection is to the l

Magnetic effects of current, a)  Explain the magnetic effects of current? ...

a)  Explain the magnetic effects of current? b)  Do the diagram to show the direction of motion of the conductor:

State the principle of working of a cyclotron, Verify the principle of work...

Verify the principle of working of a cyclotron. Write two uses of this machine. Draw a labelled ray diagram of a reflecting type telescope. Write it's any one benefit over refra

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