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

How height and pressure affect the boiling point of water, Q. How does the ...

Q. How does the height and air pressure affect the boiling point of water? Answer:- The only factor that finding the boiling point of water at any altitude is the barometr

Is light from object pass through the location of the image, In structuring...

In structuring the image does light from the object necessarily pass through the location of the image? Ans: No In reality in the case of a plane mirror (defining the obje

Black body Radiation, When Temperature increases,intensity increases,but in...

When Temperature increases,intensity increases,but in some time intensity decreases,Why?

Explain start-up current in the bulb, The cold filament resistance of a lig...

The cold filament resistance of a light bulb is 20.0). The bulb consumes 75 W when it is operating from a 120-V source. By what factor does the start-up current in the bulb

Describe the process of diffusion in cells, 1.  Describe the process of dif...

1.  Describe the process of diffusion in cells (not more than 2 pages).  2.  Derive the equation for Fick's second law. 3.  Draw a typical FRAP curve and explain its differen

Step to improve power factor, Step to improve Power Factor By using st...

Step to improve Power Factor By using static capacitor: Static capacitor is generally used to get better the power factor of the power system. As the capacitor draws leadi

Describe the principle of a moving coil galvanometer, With the help of a ne...

With the help of a neat and labelled diagram, describe the underlying principle and working of a moving coil galvanometer. What is the function of? (i) Uniform radial field

Circuit theory, what is significance of kirchoff''s law?

what is significance of kirchoff''s law?

Energy barrier, a beam of electron is incident on barrier 6eV high and 0.2 ...

a beam of electron is incident on barrier 6eV high and 0.2 nm wide. find the energy in eV these should have if 1% of them are to get through the barrier.

Electric potential , As we know that"The electric potential at a certain po...

As we know that"The electric potential at a certain point inside the electric field is defined as the amount of work done in bringing a unit positive test charge uniformly (without

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